Assurance Salvation - Can't lose Salvation

The Bible teaches that once you are saved you cannot lose your salvation. There are many, many arguments and proofs for this doctrine, including: 

Christians are predestined not just to initial salvation but to eternal salvation 

(Acts 13:47-48; Rom. 8:28-30; 9:18-24; Eph. 1:3-14; 1 Thess. 5:9-10).

Christ's death secured salvation for those for whom he died (Heb. 9:11-15).

Justification (being declared righteous and forgiven by God) cannot be lost or revoked (Rom. 5:8-10,15-19; 8:1-4,9-11,29-30; Heb. 9:11-12).

The saved/elect are given to Christ as a permanent possession (John 6:35-40; 10:25-29).

The saved/elect are kept secure in Christ by God (John 6:35-40; 10:25-29; Rom. 8:28-39; 1 Cor. 1:4-9; 2 Cor. 4:13-14; Eph. 1:13-14; 4:30; Phil. 1:6; 3:20-21; Col. 3:3-4; 1 Thess. 5:23-24; 1 Pet. 1:3-5; 1 John 2:19; 5:4; Jude 1,24-25).

Eternal life begins at conversion, and by definition may never end (John 3:14-16,36; 4:14; 5:24; 6:35-40,44-58; 10:25-29; 17:1-3; 20:31; Rom. 6:22-23; 1 Tim. 6:12; Heb. 9:15; 1 John 5:11-13,20).

God is sovereign in salvation, his will must be accomplished, and he wills the perseverance of the saints (Job 42:1-2; Isa. 14:24,27; 46:8-11; Matt. 18:12-14; John 6:35-40).