For me it expresses both peaceful procession and the passion and suffering of Christ. The rich colours speak of royal triumph, but the darkness seems to be closing in and there is more than a hint of the coming passion. The Christ figure seems already pierced. The other figures are ambiguous. Are they there to cheer, to observe, to plot or to crush?
Lord Jesus Christ,
you humbled yourself in taking the form of a servant,
and in obedience died on the cross for our salvation:
give us the mind to follow you
and to proclaim you as Lord and King,
to the glory of God the Father.
Common Worship Post Communion Prayer, Palm Sunday
For previous posts for Palm Sunday see
Image Credit: Vanderbilt Divinity Library, CC License