Eternal is simply without beginning or end.
Refer to the entry for eternity for an expanded discussion on this.
Key verse about Eternal: Praise be to the Lord your God, who has delighted in you and placed you on the throne of Israel. Because of the Lord’s eternal love for Israel, he has made you king to maintain justice and righteousness” (1 Kings 10:9, NIV).
A lifelong student of the Bible, Peter DeHaan, PhD, wrote the 700-page website ABibleADay.com to encourage people to explore the Bible. His main blog and many books urge Christians to push past the status quo and reconsider how they practice their faith in every area of their lives.