The tombs also were opened. And many bodies of the saints who had fallen asleep were raised, and coming out of the tombs after his resurrection they went into the holy city and appeared to many.
Matthew 27:52-53

These saints were resurrected at the moment of Yeshua's death, but they didn't leave their tombs until after he did. I don't know what the significance is, but I'm certain it has prophetic implications about the last days and the final judgment.