What does John 12:14 mean?

The people are cheering and celebrating Jesus as their Promised One (John 12:12–13). Palm branches are symbols of victory, hosanna is a kingly shout derived from the Psalms, and they are eagerly anticipating a Savior. All of these are fulfillments of prophecy. Daniel 9:25 even suggests a specific date, indicating a certain time from a kingly decree to the arrival of Messiah. Examining those details points to the date of March 30, AD 33, which is the Monday prior to Passover (John 12:1, 12).

Some of Jesus' fulfillments of prophecy were deliberate. This is one such example. Zechariah 9:9 speaks of the king of Israel riding on a donkey's colt; this will be cited by John in the next verse (John 12:15). This choice has other implications, as well. Conquering heroes of the ancient world would have ridden in on horses—animals used in that region for war. Jesus, on the other hand, enters on an animal that's useful only for peaceful purposes. This is the same contrast as someone riding in a modern parade in the bed of a pickup truck, rather than in the turret of a tank.

This reception for Jesus is in no small part due to His recent resurrection of Lazarus (John 12:17–18), but this has been building for some time. The people have noted how Jesus seems to fit the Scriptures, and they've responded to His power in the past (John 6:15). However, most people still expect Messiah to be a military / political ruler. Being told otherwise is not what they want to hear (John 6:26, 66). The excitement of the people for someone to challenge Rome is also exactly what the local religious leaders have feared (John 12:19). That, in fact, was their main justification for plotting to have Jesus killed (John 11:45–53).