“And behold look, the veil of the temple was split in two from top to bottom, as well as the ground (earth)quaking together with the rocks splitting apart along with the tombs opening up (gravestones broken, crypts cracked open, burial chambers exposed) even as the bodies (remains) of many deceased holy believers (dead and buried) raised again to life and leaving their tombs after this raising, they came back into the holy city and appeared alive in full view of many (eyewitnesses who encountered them).”  Matthew 27:51-53

Observations:

• Yes, this really really happened. What the Bible records accord with true factual historical reality. Likely Matthew and apostles eyewitnessed this for themselves and encountered them firsthand.  If these compound events are questionable in whole or part, so are any and all events recorded beforehand and afterward. If this is up for grabs, so is what is said or done by the other narrated characters from Christ on down to Pilate, centurion, and soldier-guards, crowds, disciples, Sanhedrin, etc. throughout Matthew’s account and the other Gospel accounts. Who and how outside the Bible itself is anyone to prove what really happened and what didn’t? If eyewitness disciples like Matthew, Peter (Mark wrote his memoirs), John and those Luke interviewed in researching his historical biography are less than certainly certifiably so and need to be vetted by today’s readers to verify, there is really no sure way of knowing who or what or how to believe beyond each reader’s personal taste.  It’s all 100% trustworthy de facto by definition as written per se, or at least some portions are less than believable based on some extra-biblical criteria measure standard of reference. Some are true, some are not. Some are real, some imagined. Some fact, some fiction. Some historic, some mythic legend. Some documentary, some embellished enhancement creative writing never actually happened but still conveying some element of higher truth.  Out of all Matthew’s text from start to finish, which is which? You get to decide rather than God in His Book settling the matter automatically up front from the getgo long before your ancestors were born. Do you get to pick your parents and birthday and hospital and personality and human traits and features in advance of being born? Do you get to pick and choose which parts of the Bible fit your notions of believability and true truth that really happened when you weren’t even around but somebody else happened to be (God Himself, Christ Himself, the Holy Spirit, eyewitness apostles and Gospel authors)?
• Jesus’ monumental death of all deaths produced accompanying signs just as His remarkable life revealed His Glory from the Father authenticating His Messiahship.
• These signs fulfilled OT Scripture prophecy about setting captives free, releasing prisoners from darkness, giving new life and light to men, superseded the obsolete Aaronic priesthood and the sacrificial system now fulfilled in His Passover Lamb Person, offered a dramatic opportunity for any witnessing them to repent and believe in this Crucified King of Israel.
• Outside God’s Holy Temple, Golgotha Calvary was Most Holy Ground eclipsing even the temple, God’s Own Personal Sacrifice being performed outside His Holy City.  Very nearby OT ancient Mt. Moriah where Abraham offered Isaac, Christ’s Cross was the tree with crossbeam branched arms suspended between heaven and earth fulfilling Ark of Covenant MercySeat Atonement Blood Offering Moses’ Law as Holy of Holies Altar-of-Altars Sacrifice-of-Sacrifices.
• Even nature itself was compelled to respond with grief parallel to Luke’s recording of bystanders’ grief of beating their breasts in public display of mourning and woe. At 6 pm Good Friday, the sun was no longer eclipsed as the remaining daylight faded into evening sunset. Earthquake tremors shook the ground and broke nearby rocky outcroppings, boulders, and hillsides with possible microburst avalanches in the surrounding vicinity of Jerusalem and suburbs.
• Who and how many were raised up out of their graves in common cemeteries (ground level) and more well-to-do crypts and rock-hewn tombs (above ground)? Many meaning possibly dozens or hundreds. Anonymous. Recently departed or buried for years. If Ezekiel 37 is any indicator or even back to Genesis 2, God had no problem restoring fresh corpses or decaying cadavers like Lazarus or skeletal remains or even dust back to original full-health life. Likely nobody famous as OT personages since Moses and Elijah were clearly identified in Transfiguration and these remained nameless. But they were known and recognized by Jerusalem residents as dearly departed relatives: parents, grandparents or even earlier ancestors as God determined. Probably similar to Lazarus, Simeon, Anna and righteous servants of the Lord as believing saints who may or may not have experienced Jesus’ ministry firsthand.
• Were they raised to life concurrently with Christ’s death on Good Friday (6 pm) and all the other accompanying signs? Most likely based on Matthew’s use of “Behold Look” = at once, just then.
• When did these dozens or hundreds of many dead buried believers now raised to life leave their gravesites on Jerusalem’s outskirts and actually enter the city to tell their story to all who would listen? Right away anytime after Friday 6 pm in the dark? Saturday morning throughout the Sabbath Day? Only after dawn Sunday morning coinciding with Jesus’ Resurrection appearances? The text is silent, but it would be hard to imagine all these many resuscitated Moses-abiding faithful law-keeping saints lingering around their ceremonially unclean gravesites on a Sabbath waiting the better part of an entire day outside with no food or water (or clothing other than grave clothes?) If they were raised up precisely when Jesus breathed his last, why wait to leave their graves and enter Jerusalem to testify? If they were raised only when Jesus resurrected, then they made their public appearances Sunday morning.
• The text gives no indication of delay between all the accompanying miracle signs when Christ died: split temple curtain, earthquake, rocks splitting apart, graves breaking open, bodies raising.  All apparently concurrent or immediately sequential on Good Friday night just as Sabbath sundown began. Christ’s bodily rest was their bodily restoration. They were the opening act as a precursor to the Main Event of Easter Sunday, just as John Baptizer was an opener for Christ’s debut and grand entrance upon the scene of history as His Spirit-Anointing-Father-Commissioned Installation as Prophet-Priest-King of God’s Kingdom inauguration.
• What happened to all these many resuscitated believers in the days and years to come? Most likely they were ordinary restorations to earth life like Lazarus and not glorified spiritual bodies like Christ Himself and Judgment Day’s Great Global Resurrection (anastasia). Like Lazarus, Dorcas, Eutychus, and others raised back to life by Jesus and apostles, they would live as long as God would allow and then die again back to the grave. Mortal not yet perfected who would have to wait like all the other saints for ultimate immortality when Christ returns in Glory at Last Day.