Immediately following the physical death of the humanity of our Lord, God caused the veil of the temple to be torn in two from top to bottom. The substitutionary spiritual death of Jesus Christ on the Cross had atoned for the sins of mankind. The sin barrier between God and man had been removed. Only then did God tear the veil in two from top to bottom. Matt. 27:50-51.
“And Jesus cried out again with a loud voice, and yielded up His spirit. And behold, the veil of the temple was torn in two from top to bottom; and the earth shook and the rocks were split.” (Matthew 27:50-51, NASB)
The veil or curtain symbolized the separation between God and man. Only the high priest and a direct descendant of Aaron could walk through the veil or curtain on the Day of Atonement to sprinkle the blood of the atoning animal sacrifice on the Mercy Seat. God Himself split the veil to convey the new reality of the removal of the sin barrier. Jesus Christ had provided the means for man’s access to God through faith in that atoning work. Heb. 10:19-20.
“Therefore, brethren, since we have confidence to enter the holy place by the blood of Jesus, by a new and living way which He inaugurated for us through the veil, that is, His flesh,” (Hebrews 10:19-20, NASB)
This second miracle was so great an earthquake that the rocks were literally split in two.
“And behold, the veil of the temple was torn in two from top to bottom; and the earth shook and the rocks were split.” (Matthew 27:51, NASB)
In Matthew 27:52-53, “saints who had fallen asleep” refers to believers who had previously died physically. “Were raised” means they had been resuscitated. This were not Old Testament saints being resurrected. Christ Himself had not yet ascended into heaven and He would be the first fruits in entering heaven. 1 Cor. 15:20-23.
“But now Christ has been raised from the dead, the first fruits of those who are asleep. For since “The tombs were opened, and many bodies of the saints who had fallen asleep were raised; and coming out of the tombs after His resurrection they entered the holy city and appeared to many.” (Matthew 27:52-53, NASB)
by a man came death, by a man also came the resurrection of the dead. For as in Adam all die, so also in Christ all will be made alive. But each in his own order: Christ the first fruits, after that those who are Christ's at His coming,” (1 Corinthians 15:20-23, NASB)
They were resuscitated for several reasons. The tremendous power of God exercised in resurrection brought believers out of the lower part of the earth. The purpose of bringing them back from the dead was a crash program of witnessing. This was necessary because all the disciples, except John, were in hiding.
The results of these miracles was salvation of many. For example, the salvation of the centurion and those with him in Matthew 27:54.
“Now the centurion, and those who were with him keeping guard over Jesus, when they saw the earthquake and the things that were happening, became very frightened and said, "Truly this was the Son of God!"” (Matthew 27:54, NASB)