This passage occurs in the Narrative Lectionary for Palm Sunday. It encompasses another RCL passage, John 12:20-33. You can find my commentary for that, here.
A brief comment here on the remainder of the passage, John 12:12-19; I find two things worth sharing.
ωσαννα: From the NET Bible:
"The expression hosanna, (literally in Hebrew, "O Lord, save") in the quotation from Ps 118:25-26 was probably by this time a familiar liturgical expression of praise, on the order of "Hail to the king," although both the underlying Aramaic and Hebrew expressions meant "O Lord, save us." As in Mark 11:9 the introductory hosanna, is followed by the words of Ps 118:25, "blessed is the one who comes in the name of the Lord." ... In words familiar to every Jew, the author is indicating that at this point every messianic expectation is now at the point of realization. It is clear from the words of the psalm shouted by the crowd that Jesus is being proclaimed as messianic king. See E. Lohse, TDNT 9:682-84."
This leads me to wonder about Messianic expectations. The text of Zechariah 9:9 is really indicative of the expectations: After a victorious military campaign, the Messiah will enter in an era of peace, worship of God and human flourishing. You could say this happens in the cross. But what a bloody battle it was...