The next day -- on the first day of the Passover ceremonies -- the leading priests and Pharisees went to see Pilate.
References for Matthew 27:62
They told him, "Sir, we remember what that deceiver once said while he was still alive: 'After three days I will be raised from the dead.'
So we request that you seal the tomb until the third day. This will prevent his disciples from coming and stealing his body and then telling everyone he came back to life! If that happens, we'll be worse off than we were at first."
Pilate replied, "Take guards and secure it the best you can."
So they sealed the tomb and posted guards to protect it.