For this cause I bow my knees unto the Father of our Lord Jesus Christ,
For this cause - resuming Ephesians 3:1, "For this cause." Because ye are so loved and favoured by God.
Bow my knees - the proper attitude in prayer. Posture affects the mind, and is therefore not unimportant. See Paul's practice, Acts 20:36; and that of the Lord Himself, Luke 22:41.
Unto the Father. Delta G f g, Vulgate, support, but 'Aleph (') A B C, Origen, omit, "of our Lord Jesus Christ." Ephesians 3:15, 'From whom,' in either case, refers to "the Father" ( Patera (G3962)), as "family" ( patria (G3965), akin in etymology) refers to Him. Still, the foundation of sonship is in Jesus Christ.