As Jesus approaches Jerusalem for the last time before His death, He intentionally fulfills important Messianic prophecies. In particular, Zechariah 9:9 says the Messiah will enter Jerusalem riding on the colt of a donkey. God had certainly prepared this colt (and its owners) ahead of time, because the disciples were allowed to take it as if there had been a prior arrangement.
Jerusalem sits atop Mt. Zion, but Bethany and Bethphage are on the other side of the Mount of Olives. Jesus’s disciples and followers began praising God and blessing Jesus as the prophecied king as they were going down the Mount of Olives, through the Kidron Valley, and up into Jerusalem proper. The Pharisees try to get Jesus to stop them from saying such things for a couple of reasons. First, they didn’t believe Jesus was the Messiah, so they didn’t want anyone else saying so. But also they didn’t want the Romans to think they were disturbing the peace, starting a revolt, and setting up a new king.
Jesus responds by saying the stones would cry out if the people were silent. This indicates that the things that are being said about Jesus at this time had been foredained by God, and nothing can thwart His decrees.
Fulfill Your promises that were made from ancient times, for You are faithful and never fail to accomplish all You intend to do.