4:1-5 People will turn away from the truth, they will grow weary of the plain gospel of Christ, they will be greedy of fables, and take pleasure in them. People do so when they will not endure that preaching which is searching, plain, and to the purpose. Those who love souls must be ever watchful, must venture and bear all the painful effects of their faithfulness, and take all opportunities of making known the pure gospel.
5. I am no longer here to withstand these things; be thou a worthy successor of me, no longer depending on me for counsel, but thine own master, and swimming without the corks [Calvin]; follow my steps, inherit their result, and the honor of their end [Alford].
watch thou—literally, "with the wakefulness of one sober."
in all things—on all occasions and under all circumstances (Tit 2:7).
endure affliction—suffer hardships [Alford].
evangelist—a missionary bishop preacher, and teacher.
make full proof of—fulfil in all its requirements, leaving nothing undone (Ac 12:25; Ro 15:19; Col 4:17).