Psalms 89:21

With whom my hand shall be established -Septuagint: “My hand shall aid him.” Luther; “My hand shall hold him.” DeWette; “With him my hand shall be continually.” Professor Alexander; “Shall ever be present.” The idea is, that God would always defend or protect him. He would not merely interpose at times, or at intervals, but he would be his constant protector. His hand would be permanently, or constantly, extended for his aid - as if it were a part of David’s own person, or were his own hand, to be used as he pleased. So God is the constant helper of his people. They may rely on his power; they may avail themselves of it, as if it were their own.