Adam Clarke on Psalms 57:2

I will cry unto God most high - He is the Most High; and therefore far above all my enemies, though the prince of the power of the air be at their head.

Unto God, לאל lael, unto the strong Good, one against whom no human or diabolic might can prevail. David felt his own weakness, and he knew the strength of his adversaries; and therefore he views God under those attributes and characters which were suited to his state. This is a great secret in the Christian life; few pray to God wisely; though they may do it fervently.

That performeth all things for me - Who works for me; גמר gomer, he who completes for me, and will bring all to a happy issue.