This verse was written by Moses as the children of Israel prepared to enter the Promised Land. Perhaps the most basic of all the attributes of God is that He "inhabiteth eternity" (Isaiah 57:15). He is "from everlasting to everlasting," the God who ever was and ever shall be.
Creatures of time cannot really comprehend the idea of past eternity. "But who made God?" children ask. "Nobody made God," we answer. "He always was." The alternative would be to believe in the eternity of "space" and "matter," but these in themselves are utterly incapable of producing our complex universe. God, however, is an adequate First Cause to explain all the effects of our infinite, intricate cosmos.
There are many other Scriptures assuring us that God has always been. "Thy throne is established of old: thou art from everlasting" (Psalm 93:2). He is "the everlasting God, the Lord" (Isaiah 40:28). And this truth applies to God the Son as well as to God the Father. The Lord Jesus could say, "I am Alpha and Omega, the beginning and the end, the first and the last" (Revelation 22:13).
We find it somewhat easier to contemplate the fact that God will live forever. Still, certain foolish men have imagined that God is dead, but "the Lord is the true God, he is the living God, and an everlasting king" (Jeremiah 10:10).
The most glorious fact of all is that this living God did also become man, in the person of Christ Jesus, and He did die. But He soon defeated death and now can say: "I am alive for evermore" (Revelation 1:18). And now, since "we believe that Jesus died and rose again, . . . so shall we ever be with the Lord" (1 Thessalonians 4:14, 17). HMM