3 Blessed is he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand.
[AD 304] Victorinus of Pettau on Revelation 1:1-3
"The Revelation of Jesus Christ, which God gave to Him, and showed unto His servants things which must shortly come to pass, and signified it. Blessed are they who read and hear the words of this prophecy, and keep the things which are written." The beginning of the book promises blessing to him that reads and hears and keeps, that he who takes pains about the reading may thence learn to do works, and may keep the precepts.

[AD 600] Apringius of Beja on Revelation 1:3
He wishes to make clear that the reading does not accomplish the obedience of the commandments, nor does the hearing display the completion of an accomplished deed. Rather, that alone is perfection, when you perform with understanding what you read and what you hear. “The time is short.” For those who accomplish these things, he does not prolong the time of recompense, but he says that the giving of the divine reward is near.

[AD 614] Andreas of Caesarea on Revelation 1:3
for the time is at hand. the time of the giving out rewards, because the brief moment of life is small in comparison to the future.
[AD 735] Bede on Revelation 1:3
Blessed is he who reads, etc. Therefore, teachers and hearers are blessed, because the short time of labor is followed by eternal joys for those who keep the word of God.

[AD 804] Alcuin of York on Revelation 1:3
Blessed is he that readeth and they that hear the words of the prophecy of this book, and keep those things which are written in it; for the time is at hand. Here it is made clear how great this book's authority is, since it is the only one among all prophecies to promise blessedness in return with a promise that is in some way specific. In saying he that readeth and they that hear, he indicated the persons of the teachers and of the listeners. What is said after that, and keep those things, pertains to both, because not the hearers of the law are just before God, but the doers of the law shall be justified. [Rom. 2:13] Then, in order to stimulate the minds of both to observe those things, he added, for the time is at hand; namely the time either for the just to be rewarded after their observance of the commandments or for the unjust to be punished after their negligence of them.

[AD 804] Alcuin of York on Revelation 1:3
QUESTION: What is meant by Blessed is he that reads and they that hear the words of this prophecy, etc.? ANSWER: The teacher and his listeners are blessed because, for those who keep the words of God, the short time of hardship is followed by eternal joys. As the Truth replied to the woman who said to him that the womb of the mother of such great son was blessed as well as her paps, even more blessed are they who hear the word of God, and keep it. [Luke 11:27-28] For he may doubtless call singularly blessed whoever is quick to understand it correctly and to put it into practice once they understand it, and, finally, as he stipulates in this same book: And he that heareth, let him say: Come, [Rev. 22:17] that is, let whoever perceives the inner light of faith and glory in their mind, also call others to it; or, as it is said concerning the same Truth, the things which Jesus began to do and to teach. [Acts 1:1]

[AD 990] Oecumenius on Revelation 1:3
He does not call them blessed who are readers alone, because there would be many who would be blessed because there were many readers, but it is meant for those who hear and keep the warnings in the prophecy, and those who faithfully keep and observe its commands as divine laws.

For he says, the time is at hand. For everyone who keeps the commandments of God the time of blessedness is at hand. That is what he means or he could mean that the conclusion of what he said is close at hand. What is meant by at hand has already been explained.

[AD 1349] Nicholas of Lyra on Revelation 1:3
Blessed He tells the hearers to listen to the power of the book; that is, how to get blessedness, saying: Blessed is he that reads Referring to the doctors of the Church, who hear Referring to pious students, The words of this prophesy, By keeping in mind. and keeps those things that are written in it; By enduring the future trials, and the reason is added: For the time is at hand, already passing, as if to say, the suffering is brief and the reward of blessedness is forever.