Palm Sunday is found:

whenever we are serving a noble and unpopular cause with selfless devotion, holding to the ideals of truth and justice;

whenever we are seeking to uplift the fallen, to comfort the brokenhearted, to strengthen and encourage the weak and hopeless;

whenever we are working bravely and persistently in the face of abuse and criticism to establish more equitable relations in the world;

whenever we are sacrificing our lives in behalf of what we believe to be the service of love for all humanity.

That is Palm Sunday!

Source: David O. Rankin, Dancing in the Empty Space (Skinner House Books, 2001).