“one God and Father of all, who is above all, and through all, and in you all.” (Ephesians 4:6, NKJV)
The ancient world had many, many gods. Paul acknowledged the obvious, “For even if there are so-called gods, whether in heaven or on earth (as there are many gods and many lords)” (1 Cor. 8:5). Times have not changed. There are literally millions of gods in Hinduism. The Church of Jesus Christ of Latter-day Saints (Mormons) teach there are many gods over many worlds ((Joseph Smith, Jr., History of the Church, VI:474-475), even as their Book of Mormon says there is one God (Alma 11:26-31). But, the one true God has revealed His power and deity through creation (Rom. 1:20). He has revealed His character and His will through Jesus Christ (Col. 1:15; Heb. 1:1-2). There is no other God than the God of the Bible (Isa. 44:6). While there are many things about God we do not know, we can understand what He has revealed of Himself in nature and in His Scriptures. He is our Creator (“Father of all,” Acts 17:25, and heavenly Father of His schildren, Matt. 6:9). He is Sovereign (“above all,” Acts 11:26). He sustains our lives (“through all,” Acts 17:28). And, He lives with His people (“in you all,” Jno. 14:23). He is the great Unifier of Christians in the (one) body of Christ, the church (Eph. 1:20-23). His reward is with all who diligently seek Him and worship Him in spirit and truth (Jno. 4:23-24; Heb. 11:6).