This passage emphasizes the importance of suffering for the sake of the gospel and encourages Timothy toward that end (1:8; compare 1 Timothy 1:15; 2:5–6).
He has saved us … our Savior, Christ Jesus: God and Christ are both described as Savior (see 1 Timothy 1:1; 2:3–4).
called us to a holy calling: Salvation and godliness are connected (see 1 Timothy 3:14–16; 5:8; Titus 2:11–14; 3:4–7; Ephesians 2:10).
and by the grace He granted us: Grace is not given because we deserve it, but because God grants it (see Romans 3:23–24; 5:6–11; Ephesians 2:8–9; Titus 3:5).
by His own purpose … before time began: See Titus 1:2; John 17:24; Ephesians 1:4, 11; 1 Peter 1:20; Revelation 13:8. Salvation does not depend on human effort but only on God's grace.