Rav Pinchas pointed out that King David called five times upon the Holy One to arise in the book of Psalms. "Arise, O Lord, save me, O my God" (Psalms 3:7). "Arise, O Lord, in Your anger" (Psalms 7:6). "Arise, O Lord, do not let man prevail" (Psalms 9:19). "Arise, O Lord, O God, lift up Your hand; forget not the humble" (Psalms 10:12). "Arise, O Lord, disappoint him, cast him down" (Psalms 17:13).
Five calls to rise, and the sages noticed that in none of these moments did the psalm record a direct answer. The Holy One, blessed be He, seemed to remain seated.
Rav Pinchas taught that God Himself responded to David's repeated summons with this message: "My son, though you call upon Me many times to arise, I will not arise for your sake alone. But there is a moment when I do arise. When you see the poor oppressed and the needy sighing, then I will arise."
The proof is in Psalms 12:5, spoken in God's own voice. "Because of the oppression of the poor, because of the sighing of the needy, now I will arise, says the Lord. I will place him in the safety that he longs for."
A king pleading for himself may or may not wake the Throne. A cry from the poor always does (Bamidbar Rabbah 75).