Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
Perpetuity of existence. The doctrine of immortality is taught in the Old Testament. It is plainly implied in the writings of Moses (Gen. 5:22, 24, 25:8, 37:35, 47:9, 49:29, comp. Heb. 11:13-16; Ex. 3:6, comp. Mt. 22:23). It is more clearly and fully taught in the later books (Isa. 14:9; Ps. 17:15, 49:15, 73:24). It was thus a doctrine obviously well known to the Jews.
With the full revelation of the gospel this doctrine was "brought to light" (2 Tim. 1:10; 1 Cor. 15; 2 Cor. 5:1-6; 1 Th. 4:13-18).