2 Thessalonians 3:3

The Lord is faithful. With man’s unfaithfulness, especially that of the Jews, who turned their backs on God’s truth, is contrasted the invariable faithfulness of God (see on 1 Cor. 1:9). Paul could personally testify to the Lord’s trustworthiness, because of the promise of deliverance and its fulfillment in Corinth (Acts 18:9–17).

Stablish. Gr. stērizō, “to confirm,” “to establish,” “to strengthen.” Paul had already prayed that his converts might be established (ch. 2:17); now he expresses confidence that this will be done.

Keep you from evil. Literally, “guard you from the evil,” or “guard you from the evil [one].” The reference may be to evil in general, or to Satan, the evil one (cf. Matt. 13:19, 38; Eph. 6:16, RSV; 1 John 2:13, 14; 3:12; 5:18, RSV). A reference to Satan is fitting in this epistle where Paul has brought into such prominence the work of Satan and his agents (see on 2 Thess. 2:3–12). The apostle assures his readers that the lord whom they serve will faithfully protect them even from the worst of enemies.