In God, is underived and absolute: "who only hath immorality." In creatures, it is dependent upon the will of God. The immortality of the soul is argued from its boundless desires and capacities, is unlimited improvement, its desert of future punishment or reward, etc. All arguments, however, are unsatisfying without the testimony of Scripture. Christ "hath brought life and immortality to light through the gospel," 2 Timothy 1:10: the immortal blessedness of Christians, including the resurrection of the body, is by virtue of their union with Christ, Joshua 14:15. The everlasting woe of the wicked, the punishment of their sins, runs parallel with the eternal life of the redeemed, Matthew 25:46.
Source: ATS Bible Dictionary
Immortality
Perpetuity of existence. The doctrine of immortality is taught in the Old Testament. It is plainly implied in the writings of Moses (Genesis 5:22,24; 25:8; 37:35; 47:9; 49:29, Compare Hebrews 11:13-16; Exodus 3:6, Compare Matthew 22:23). It is more clearly and fully taught in the later books (Isaiah 14:9; Psalms 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 Timothy 1:10; 1 Corinthians 15; 2co 5:1-6; 1 Thessalonians 4:13-18).
Source: Easton's Bible Dictionary
Immortality
IMMORTAL'ITY, n. The quality of never ceasing to live or exist; exemption from death and annihilation; life destined to endure without end; as the immortality of the human soul.
--Jesus Christ, who hath abolished death, and hath brought life and immortality to light through the gospel. 2 Tim.1.
1. Exemption from oblivion.
2. Perpetuity; existence not limited; as the immortality of a corporation.