Pīti: Gladness that lifts the body
Pīti is joy arising in the body before anything has been settled. The shout goes up while the king is still out on the road, still a figure in the distance, the way a household starts cheering at the first sound of footsteps on the path. Broken walls and thin harvests are still the facts on the ground in Zion, and the gladness comes anyway, resting entirely on who is arriving.
Dhammarāja: A king who rules by dhamma
Dhammarāja names a ruler whose whole claim rests on righteousness. Take "righteous" as the ground he stands on: it is what makes him king, and it is what he carries into the city with him, since he brings no treasury and no army. A king like this wins the way daylight fills a valley, quietly, with nothing forced.
Nivāta: Humility, low to the ground
Nivāta is a mind that has given up measuring itself against others. "Lowly" is a measurement taken twice here, how far off the ground he sits and how high he holds himself in his own estimation, and the second produces the first. Anyone standing in the road can reach up and touch a man on a donkey, which is the reason for coming that way.
Avihiṃsā: Harmlessness
Avihiṃsā is the settled intention to injure nothing. A donkey is a farm animal, borrowed on market days for grain sacks and firewood, so a king who arrives on one has left the war horse and the battle chariot out of the procession altogether. Nobody lining that road needs to be afraid of him, and his harmlessness is itself the announcement.
Yogakkhema: Safety, the yokes lifted off
Yogakkhema is the relief of being out from under every harness. "Having salvation" holds it as something already in his hands as he rides, the way someone walks in from the field with the harvest already in their arms. For a city that has been one empire's property after another, safety arrives as a strap being unbuckled, and the animal under him wearing the only harness left in sight.