Jamieson, Fausset & Brown

Though He WAS (so it ought to be translated: a positive admitted fact: not a mere supposition as were would imply) God's divine Son (whence, even in His agony, He so lovingly and often cried, Father, Mat 26:39), yet He learned His (so the Greek) obedience, not from His Sonship, but from His sufferings. As the Son, He was always obedient to the Father's will; but the special obedience needed to qualify Him as our High Priest, He learned experimentally in practical suffering. Compare Phi 2:6-8, "equal with God, but . . . took upon Him the form of a servant, and became obedient unto death," &c. He was obedient already before His passion, but He stooped to a still more humiliating and trying form of obedience then. The Greek adage is, "Pathemata mathemata," "sufferings, disciplinings." Praying and obeying, as in Christ's case, ought to go hand in hand.