Here is a condensed version of the great Cornelius a Lapide
Ver. 52. And the graves were opened, and many bodies of the saints which slept arose. This was immediately on Christ’s death (as S. Matthew implies), to signify that it was wrought by the power of His Passion, and consequently that by the same power death was overcome, and life restored to mankind. So Bede, Theophylact, and S. Jerome, who says, “The graves were opened in token of the future resurrection.” So, too, S. Ambrose (cap. x. on Luke). And S. Hilary says, “Illumining the darkness of death, and lighting up the gloom of the pit, He robbed death of its spoils, in order to [mark? word missing] the resurrection of the dead who are now asleep.” But yet they came not forth from their graves till after Christ’s resurrection (see ver. 53). For S. Paul terms Christ “the first-born from the dead” (Col. i. 18), and “the first-fruits of them that rise again” (1 Cor. xv. 20). For Christ by His death procured resurrection both for Himself and for us. It was therefore but right that, when He had overcome death, He should be the first to rise as its conqueror, and others after Him. (So Origen, S. Jerome, and Bede.)
They rose, then, that Christ might confirm the truth of His resurrection, by those His companions who announced it; and, again, that in and through them Christ might manifest the power of His Passion; that just as the souls of the Patriarchs were freed by it from the pit, so, mystically, would men’s souls, which were dead in sin, be now quickened by His grace, and themselves rise gloriously at last to a blessed and eternal life.
Did, then, these saints die again after their resurrection, or continue in life and glory? Some think they did die, and are to rise again at the last day, and this from S. Paul’s words, “That they without us should not be made perfect.” (See S. Augustine, Epist. xcix. ad Evodium.) Others suppose, and more correctly, that they died no more, but were raised up to life immortal. Because it was but fitting that Christ should manifest at once in their resurrection the power of His own. It was also meet that happy souls like these should be united only to glorious and immortal bodies. But their happiness would have been but brief, and their misery greater, if they had died again so speedily. It would have been better, indeed, if they had not risen at all. It was also but fitting that they should adorn Christ’s triumphant ascension, as captives redeemed by Him, and the spoils He had won from death; and, lastly, that He should have them with Him in Heaven, and that His human nature, enjoying their presence and society, might never be solitary and void of human consolation. So Origen, S. Jerome, S. Clemens Alex. (Strom. lib. vi.), and others. The words “without us” do not refer to the day of judgment, but to the resurrection of Christ and Christians. (See notes on Heb. xi. 40.)
But it is not clear who these saints were. Probably those, in the first place, who were specially connected with Christ, either by kindred, or promise, or type and figure, or by faith and hope, or else by chastity and holiness; as Adam, Abraham, Isaac, Melchisedek, David, who wished to be buried in the promised land, and thus be partakers of Christ’s resurrection. Job, also, and Jonah, as types of the resurrection; Moses, Joshua, Samuel, Isaiah, and the other Prophets. Daniel, also, and his three companions (though their bodies are at Rome). Eve, also (some suppose), as well as Adam, though Lorinus considers that the Blessed Virgin was the first woman raised from the grave, as Christ Himself was the first-fruits among men. Those, also, who died but recently; as Zacharias, Simeon, S. John the Baptist (though his head is shown at Rome and Amiens, his finger at Florence). Raymundus also (lib. de Bono Latrone, cap. xiii.) mentions the penitent thief, though S. Augustine (contr. Felician cap. xv.) says, but only by the way, that he was reserved for the future resurrection. There were also many more (especially those mentioned in Heb. xi.) outside Judæa, for “many bodies of the saints arose.” For it was indeed quite in harmony with the profuse magnificence of Christ that a crowded procession of the saints who then arose should dignify His resurrection and ascension.
**Verse 53- **Went into the Holy City. Jerusalem, so called because of the temple worship, of the many saints who had been there, and of the institution of the Church therein by Christ the King of Saints.
And appeared unto many. To the Apostles, and disciples, and also to the Jews, to persuade them to believe in the resurrection. “That by their resurrection,” says Euthymius, “others might be the more assured, by considering that He who had raised them had much more surely raised Himself.”