Interesting post. The question of a literary relationship between Revelation and 4 Ezra would seem at first glance less likely than the possibility of both being cognate works, since both would have been written supposedly around the same time (e.g. at the close of the first century), but it has also been recognized that 4 Ezra has been compiled from earlier apocalyptic materials and the passage you cite is part of the so-called Salathiel Apocalypse that is presumed to lie behind the present text of 4 Ezra. The earliest clear quotation from either 4 Ezra or one its sources, aside from Revelation, appears to be Barnabas 12:1:
Barnabas 12:1: "Similarly he once again gives an explantation about the cross in another prophet, who says: 'And when shall these things be accomplished (pote tauta suntelesthésetai)? The Lord says: "When a tree falls over and rises again, and when blood drips from a tree (hotan ek xulou haima staxé)" ' ". 4 Ezra 1:22-23: "Thus says the Lord Almighty: 'When you were in the wilderness ... I did not send fire upon you for your blasphemies, but threw a tree into the water and made the stream sweet' ".
4 Ezra 4:33: "Then I answered and said, 'How long and when will these things be? For our years are few and evil.' "
4 Ezra 5:4-5: "If the Most High grants that you live, you shall see the earth thrown into confusion after the third, and the sun shall suddenly shine forth at night, and the moon during the day. Blood shall drip from wood, and the stone shall utter its voice".
Since the author of Barnabas appears to combine elements drawn from different places in 4 Ezra, he appears to know the work as it has been redacted together rather than one of its sources. Interestingly, the quotation includes the same phrase from 4 Ezra 4:33 that also appears in some form in Revelation 6:10:
Revelation 6:9-11: "When he opened the fifth seal, I saw under the altar the souls of those who had been slain because of the word of God and the testimony they had maintained. They called out in a loud voice, 'How long (heós pote), Sovereign Lord, holy and true, until you judge the inhabitants of the earth and avenge our blood?' Then each of them was given a white robe, and they were told to wait a little longer, until the number of their fellow servants and brothers who were to be killed as they had been was completed." 4 Ezra 4:33-37, 42: "Then I answered and said, 'How long and when will these things be? Why are our years few and evil?' He answered me and said, 'You do not hasten faster than the Most High, for your haste is for yourself, but the Highest hastens on behalf of many. Did not the souls of the righteous in their chambers ask about these matters, saying, "How long are we to remain here? And when will come the harvest of our reward?" And Jeremiel the archangel answered them and said, " When the number of those like yourselves is completed, for he has weighted the age in the balance, and measured the times by measure, and numbered the times by number, and he will not move or arouse them until that measure is fulfilled." ' ... In Hades the chambers of the souls are like the womb."
Here the parallels are compelling because both scenes picture the dead martyrs in the abode of the dead (Hades, "under the altar") asking the Lord how long they will have to continue to wait, and they are told to wait until the (1) number of (2) those like themselves had reached its (3) completion. The questions posed to Uriel in 4 Ezra also have parallels in the disciples' question in Mark 13:4, regarding when the prophesied things were to occur:
Mark 13:4: "When will these things happen (pote oun tauta estai)? And what will be the sign that they are about to take place (ti to sémeion hotan melé tauta ginesthai)? 4 Ezra 4:33, 35, 51-52: "Then I answered and said, 'How long and when will these things be? For our years are few and evil... How long are we to remain here? And when will come the harvest of our reward? ... Then I prayed and said, 'Do you think that I shall live until those days? Or who will be alive in those days?' He answered me and said, 'Concerning the signs about which you ask me, I can tell you in part, but I was not sent to tell you concerning your own life, for I do not know' ".
Compare the wording in Greek with the 4 Ezra citation in Barnabas (cf. pote tauta suntelesthésetai vs. pote oun tauta estai/tauta ginesthai). There are also paralels between 4 Ezra 4:33, 35, 51-52 and 2 Baruch, a cognate apocalypse from the same period: "The present years are few and evil, and who can inherit that which is unmeasurable in this short time... How long will corruption remain, and until when will the time of mortals be happy, and until when will those who pass away be polluted by the great wickedness of this world?" (2 Baruch 16:1, 21:19). There are other considerable parallels with Revelation, especially the following:
Revelation 7:9, 13, 14:1, 3: "After this I looked and there before me was a great multitude that no one could count, from every nation, tribe, people and language, standing before the throne and in front of the Lamb. They were wearing white robes and were holding palm branches in their hands....Then one of the elders asked me, 'These in white robes, who are they, and where did they come from?' ".... Then I looked, and there before me was the Lamb, standing on Mount Zion, and with him 144,000 who had his name and his Father's name written on their foreheads, ... and they sang a new song before the throne and before the elders and the four living creatures". 4 Ezra 2:42-46: "I, Ezra, saw on Mount Zion a great multitude, which I could not number, and they all were praising the Lord with songs...Then I asked an angel, 'Who are these, my lord?' He answered and said to me, 'These are they who have put off mortal clothing and put on the immortal, and they have confessed the name of God; now they are being crowned and receive palms'. Then I said to the angel, 'Who is that young man who places crowns on them and puts palms in their hands?' ". 4 Ezra 13:32-40: "And they shall plan to make war against one another, city against city, place against place, people against people, and kingdom against kingdom. And when these things come to pass and the signs occur which I showed you before, then my Son will be revealed, whom you saw as a man coming up from the sea. And when all the nations hear his voice, every man shall leave his own land and the warfare that they have against one another, and an innumerable multitude shall be gathered together, as you saw, desiring to come and conquer him. But he will stand on the top of Mount Zion. And Zion will come and be made manifest to all people, prepared and built ... and he will reprove the assembled nations for their ungodliness.... And as for your seeing him gather to himself another multitude that was peaceable, these are the ten tribes which were led away from their own land into captivity in the days of King Hoshea, whom Shalmaneser the king of the Assyrians led captive; he took them across the river, and they were taken into another land".
Note that the "innumerable multitude" is drawn from all the nations of the earth, while "another multitude" of 4 Ezra which comes together with the Son of Man at Mount Zion is drawn from the ten lost tribes of Israel -- somewhat similar to the 144,000 of Revelation which is sealed from the tribes of Israel.
The main question is whether we have direct dependence here or cognate traditions. The relationship between 4 Ezra and the "Little Apocalypse" of Mark (and Matthew, Luke) is especially close, so dependence is quite possible between Mark and a precursor of the present text.... but the relationship is hopelessly muddled due to the lack of evidence, not in the least the lack of any Greek or Aramaic version of the text (which survives only in Latin and a Syriac translation).
