Finding a young donkey, Jesus sat on it, as it is written:
14. And Jesus having found a young ass. This part of the history is more minutely related by the other Evangelists, who tell us, that Christ sent two of his disciples to bring an ass, (Matthew 21:1; Mark 11:1; Luke 19:29.) John, who was the latest writer of all the Evangelists, reckoned it enough to notice briefly the substance of what had been stated by...
This story of Christ's riding in triumph to Jerusalem is recorded by all the evangelists, as worthy of special remark; and in it we may observe, I. The respect that was paid to our Lord Jesus by the common people, Joh 12:12, Joh 12:13, where we are told, 1.
Commenting on John 12:12-19
And Jesus, when he had found a young ass,.... Which he sent his disciples for, to a neighbouring village, and they brought to him: sat thereon, as it is written; in Zac 9:9 though some part of the words seems to be taken out of Isa 62:11; See Gill on Mat 21:5; and so Nonnus paraphrases it here, "that it might be fulfilled which Esaias said".