This verse contains a new argument for the constancy and immutability of St. Paul's doctrine, drawn from the subject matter of his preaching; namely, Jesus Christ. As Christ is always one and the same, whom himself and other ministers did preach, so is our doctrine one and the same also.
Note here, 1. The subject matter of St. Paul's preaching, what was the sum of his own and his companion's sermons, (Sylvanus and Timotheus,) it was not his own imagination, or the Jewish rites and ceremonies, but Christ in his nature and offices; The Son of God, Jesus Christ, was preached among you by us.
Note, 2. The happy unity and accord which was found among all these ministers, St. Paul, Sylvanus, and Timotheus, in preaching Christ.
O blessed agreement! when all the ministers of God with one consent conspire and agree to advance and extol our Lord Jesus Christ.
Note, 3. That the course of St. Paul's and his assistants' preaching; Christ Jesus, fixedly and unchangeably the same; not yea at one time, and nay at another.
Learn hence, That it is a proper note of God's truth, and the true preachers thereof, that they are always one and the same, always yea, and not nay; there is no change or contrariety in their doctrines.