For this cause - Resuming the thread of Eph 3:1, “For this cause.” Because ye have such a standing in God’s Church [Alford].
bow my knees - the proper attitude in humble prayer. Posture affects the mind, and is not therefore unimportant. See Paul’s practice (Act 20:36); and that of the Lord Himself on earth (Luk 22:41).
unto the Father - The oldest manuscripts omit “of our Lord Jesus Christ.” But Vulgate and some very old authorities retain them: Eph 3:15, “From whom,” in either case, refers to “the Father” (Patera), as “family” (patria, akin in sound and etymology) plainly refers to Him. Still the foundation of all sonship is in Jesus Christ.