תהילים קי:ב פירוש: רש״י

The staff of [This is] an expression of support, as (above 105:16): “every staff of bread.”

The staff of your might the Lord will send from Zion When you return from the war and your men are weary and in pursuit, the Lord will send you Malchizedek, king of Salem, to bring out bread and wine (Gen. 14:14).

rule in the war.