Paul is so eager to come to the subject matter of his epistle, the righteousness of faith in opposition to the righteousness of works, that already in the title he must speak his mind. He did not think it quite enough to say that he was an apostle 'by Jesus Christ'; he adds, 'and God the Father, who raised him from the dead.'
The clause seems superfluous on first sight. Yet Paul had a good reason for adding it. He had to deal with Satan and his agents who endeavored to deprive him of the righteousness of Christ, who was raised by God the Father from the dead. These perverters of the righteousness of Christ resist the Father and the Son, and the works of them both.
In this whole epistle Paul treats of the resurrection of Christ. By His resurrection Christ won the victory over law, sin, flesh, world, devil, death, hell, and every evil. And 12this His victory He donated unto us. These many tyrants and enemies of ours may accuse and frighten us, but they dare not condemn us, for Christ, whom God the Father has raised from the dead is our righteousness and our victory.
Do you notice how well suited to his purpose Paul writes? He does not say, 'By God who made heaven and earth, who is Lord of the angels,' but Paul has in mind the righteousness of Christ, and speaks to the point, saying, 'I am an apostle, not of men, neither by man, but by Jesus Christ, and God the Father, who raised him from the dead.'