Paul's Introductory Greeting (Galatians 1:1-10).
‘Paul, an Apostle, not from men neither through man, but through Jesus Christ, and God the Father who raised him from the dead.
Paul as usual begins with his credentials. He is an Apostle (apostolos - ‘one sent out'). And he stresses that this was not by man's appointing, nor had he received his authority from men. Rather He was appointed by Jesus Christ, the risen Lord Himself, and by God the Father, the One Who raised Jesus Christ from the dead. Indeed He has the authority of one who has seen the risen Christ and has been called by Him.
The normal basis of Apostleship was to have been an eyewitness to the life and ministry of Jesus, and especially an eyewitness of the resurrection (Acts 1:21-22). We do not know whether Paul had witnessed much of Jesus' life and teaching, but we do know that he was a witness to having seen the risen Lord (Acts 9:1-9), as He regularly emphasised (Acts 22:4-21; Acts 26:9-18). However, his own claim to Apostleship lay in the special calling he had received from God, a calling which, he emphasised, was later ratified by the Twelve Apostles.
Thus he claims that he does not write to them speaking on his own authority. Rather, as his conversion experience reveals, he has been chosen by God and sent by God, Who alone is the source of his authority and his understanding, so that he speaks in His Name. He will argue this more strongly shortly. This, however, is in complete contrast with the legalists who have come among them, whom he is seeking to refute. For their appointment, if such they have, is of men. They bring only a human message, not a God revealed one.