Should we pray in behalf of the faithful angels that Jehovah strengthen them to remain faithful? There is no Biblical precedent for such, and there is no argument in our publications for such prayers to be made.
The tree of life in the Garden was not a supernatural tree. What ever kind of fruit-bearing tree it was, it had approximately the life-span that other trees of its kind had. Therefore, within the life-span of that tree that bore edible fruit, Jehovah expected the perfect man Adam to have qualified himself for grant from Jehovah to eat of that tree's fruit in order to signify that He had given the man the right to everlasting life. The man disqualified himself; so, Jehovah had to block approach to that tree so that the man might not get to it and eat of it and thereby have to live to time indefinite (forever).
The angels aware of the events in the Garden were already far older than Adam, but Jehovah apparently had yet to make irreversible grant of everlasting life to ALL of the angels. That Satan and, later on, some more angels besides Satan made themselves into devils is evidence of God's wisdom in His not having previously made the pronouncement 'I grant all my heavenly sons the right to everlasting life.' (Really, though, was it ever Jehovah's intention to make formal pronouncement someday to the effect that He has come to know that all His faithful angels are beyond temptation to rebel against Him, and that He acknowledges their right to everlasting life? There will be more on this below.
One day (at the end of Christ's 1000-year rule), men will be perfected, and will become children of God, just as many of them as will pass the final test. Such ones will be justified -- given the right -- to everlasting life.
Whether Jehovah, since Satan's rebellion, or since Noah's day, has ever declared of certain faithful angels besides His only-begotten Son that He has found them to be beyond temptation to rebellion, and has accordingly pronounced His acknowledgment of their right to everlasting life, or whether such pronouncement(s) will eventually prove to be the case for all faithful angels, is an arguable matter. Aside from the matter of formal decrees/pronouncements, however, consider this question: If Jehovah has already satisfied Himself that all His faithful, heavenly sons have attained to an unbreakable integrity in themselves, then would it not be pointless to pray for them to remain faithful -- just as pointless as it would be were we now to pray that Jesus be strengthened to endure, to remain faithful?
Jehovah has confidence and trust in His angelic sons. He did not have to appoint at least two if not more cherubs to guard against possibility that Adam might try to get to the tree of life and reach out his hand and take some of its fruit and eat it and thereby live forever. Jehovah, by His holy spirit alone, could have guarded against way to the tree of life; however, was not such use of those angels a wonderful way for Jehovah to tell His sons that He trusted them with His own reputation? Do we not have argument, then, that Jehovah must have looked into the "hearts" of some angels standing beside the tree of life and found that they were already beyond temptation to conspire and rebel against Him? I like to think that is a reasonable conclusion, as also that Jehovah had already seen as much in very many others of His heavenly sons, too. Whether He made in Heaven any formal pronouncements as to what He was finding, or whether He was waiting or is still waiting for the right time to do so -- or whether He thinks it is something that need never be formally pronounced -- is maybe something about which we will learn more in the new world, if not before by someone who presents better argumentation than that which informs this post.
One thing we do know. The death that is experienced by a superhuman person as a superhuman person is the second death, and so the demons have only themselves to blame for the judgment of second death that will eventually claim them. The death they experience cannot be attributed to any imperfection in them for which they had no choice in the matter, for their sin is due to another thing, namely, their deliberate, willfully wicked choice to rebel against Jehovah. The judgment against them is second death, but we will make more comment on that below.
First, though, what more can we say about the angel that visited Jesus in the garden of Gethsemane in order to strengthen Jesus? Even a perfect human can be comforted so that he might thereby be helped to endure in his organism that which, absent that comfort, could the more easily mean temporary unconsciousness or paralysis for him. We ought not to reason that we can make reference to the fact that an angel visited Jesus in the garden of Gethsemane as basis for the argument “Jesus was strengthened against possibility that he might compromise his integrity in what was to befall him in the next few hours; therefore, if the perfect man Jesus needed to receive strength against possibility that he might make moral compromise (do a sin), then why not pray that the perfect angels receive strength to the same end, too?” What is wrong with that argument?
Jesus was sorely troubled -- stunned and deeply grieved even unto death -- because he knew he was soon to be front and center as a lightning rod for attracting the nation's rulers' unjust condemnation of himself on basis of false charges that he had blasphemed Jehovah. That grief in Jesus betokened neither predisposition nor temptation to moral or spiritual failure/unfaithfulness in him; nevertheless, Jesus' grief in the garden (Mark 14:32-36) had to be addressed so that he would not lose too much strength in his organism, but retain enough strength critical for his maintaining consciousness and speech until death.
The angel's visit to Jesus in the garden of Gethsemane reassured Jesus that his Father was already taking steps -- beginning in the night that He sent the aforementioned angel to Jesus while he was yet so sorely troubled in the garden -- to help His Son to endure in his organism ill treatment, this so that he might not collapse too soon before his being lifted up on the torture stake. We do not, therefore, conclude that the angel's visit was out of concern either in the angels or in the Father that Jesus, unless he received strength from a visit by an angel, might not keep integrity, might not remain faithful.
So, for reiteration -- and for more, related things that I argue we should keep in mind when considering answer to the question ”Should we pray in behalf of the angels, that they remain faithful?” -- consider the following:
(1) Adam was never to be granted immortality; however, he stood in line to have been declared worthy of everlasting life, and would have been so declared had he passed the test, and then Jehovah would have signified as much for Adam by letting him eat of the tree of life. Adam failed his test. Still, even as a sinful creature, Adam could have lived forever had Jehovah not taken the steps necessary to prevent Adam from getting hold of fruit from the tree of life -- Genesis 3:21-24.
(2) Having the right to everlasting life does not mean that the owner of that right has ceased to be a free moral agent. It was because he freely chose to become so disciplined in righteousness that it has become psychologically impossible for him to rebel that is the basis for his acquiring the right to everlasting life.
(3) The angels are free moral agents. Only one of their number would ever come to have immortality, namely, Michael the archangel. Obviously, Jehovah had satisfied himself that Michael had so disciplined himself in righteousness that he had come to be beyond possibility of rebellion against Jehovah. Jehovah had the utmost confidence that His Son would not rebel even should he become a human subject to the machinations of Satan, and facing a certain and excruciatingly painful death. Jehovah knew that His Son would come to remember and appreciate the training he had previously received in Heaven before the flesh-taking event in Mary's womb. And so it happened: the man Jesus the Nazarene was anointed with holy spirit in the Jordan River, and the Heavens were opened up to him. Jesus, though in a reduced personhood -- having a personhood less than the angels' --, came to know within himself that he loved his Father with the same love that he had for his Father before ever he had become a human, and so it seems reasonable to say that Jesus accordingly knew that he would never rebel against his Father. Certainly, though, there came a point in time when Jehovah could infallibly conclude that His Son would never rebel, and accordingly deserved the name Michael, because if ever rebellion were to break out among Jehovah’s rational creatures, then Michael must have a leading role in the vindication of Jehovah’s sovereignty. He got that trust placed in him by his Father obviously well before Jehovah created mankind, and certainly long before He gave His Son immortality.
The question becomes this: did Jehovah know as much about some of the other of His angelic sons -- that some more of His sons had also come to be beyond possibility of rebellion against Jehovah? Obviously, we cannot say that before Jehovah created man, He had come to know as much for all His angelic sons, because many of them did rebel after man’s creation, beginning with the one identified as Satan the Devil. We avoid confusing the issue if we do not harbor the thought that only those who receive immortality are beyond possibility of rebellion; we ought not to reason that if one is not immortal, then he is not beyond possibility of rebellion, and if not beyond possibility of rebellion, then we should pray in his behalf, including in behalf of the not-immortal (mortal) angels. The fact of the matter, though, is that immortality doesn't necessarily come about as a reward for a free moral agent who has made good on his ability to so discipline himself that he comes to be beyond rebellion. Did not Adam once stand to exemplify as much (i.e., stand to exemplify that one can discipline himself so as to come to be beyond possibility of rebellion), and that he would have if he had kept on listening to his heavenly Father? In that event, Jehovah would have signified as much by letting Adam eat of the tree of life so that ever after that event, Jehovah would never have concerned Himself in the least as to whether Adam might yet prove unfaithful some day, and yet still have to live forever, even though he still would not have been immortal, for immortality is a thing Adam would never have received . . . "no matter what." Only Jehovah, Jesus, and the 144,000 in Heaven have immortality; nobody else will ever have it. Do we not rightly conclude, then, that there will be many rational creatures granted the right to irreversibly everlasting life by virtue of Jehovah's ability to know when a servant of His has freely chosen to discipline himself so as finally to be beyond possibility of rebellion? How many of the angels are there who have already so disciplined themselves? Does it not stand to reason that some, if not most or even all of His angelic sons presently in the Heavenly court, have so disciplined themselves in Jehovah’s righteousness that they have come to be beyond rebellion so that they, too, will by no means be harmed by the second death? If the argument stands, then is it not pointless to pray in their (the angels’) behalf that they be strengthened against moral compromise?
Imperfect humans as imperfect humans can so discipline themselves in Jehovah's righteousness as finally to be beyond possibility of rebellion against Jehovah. There are thousands who have done so by now, and these thousands have got the final sealing so that they have been "grant[ed] to eat of the tree of life, which is in the paradise of God" -- which symbolizes that Jehovah has the utmost confidence in His bestowing immortality upon them so that they will have to live forever, for they "will by no means be harmed by the second death"; they have immortality. By the time the great tribulation breaks out, Jehovah will have finished the final sealing of the earthly remnant of the 144,000, and then when they die, they, too, will share in the first resurrection, and eat of the tree of life in the paradise of God. As imperfect humans who had come to be beyond possibility of rebellion against Jehovah, and then as spirit creatures in Heaven, those of the 144,000 have ever had and always will retain free moral agency.