I have heard all my life that God is eternal. What does the Bible mean when it says that God is eternal?
What you heard all your life about God being eternal is true, the Bible declares it (Gen. 21:33; Ps. 90:1-2; John 1:1; 1 Tim. 1:17; Heb. 9:1; Rev. 1:1). This means that God is without beginning or end, and in His being He does not experience His own existence in sequence, one moment after another. God experiences and possesses simultaneously the full, unlimited duration of His eternal being in an eternal now. God does not have a past or a present, but He lives in eternity, an everlasting present where the past, present, and the future are equally vivid to Him.
Since time is a part of the physical and created universe, the constraints of time do not and cannot limit God. God does not have to wait for a moment of time to happen. We experience time in sequence, one moment after another. For example, when a couple sets a date for their marriage, in most cases, they must wait through time measured in seconds, minutes, days, weeks, and months for the day to come. God on the other hand, does not have to wait for time to pass. He does not have to wait for any future moment to come. As far as God is concerned, everything that is going to occur has already occurred.