We all believe in our hearts and confess with our mouths1 that there is only one God,2 who is a simple3 and spiritual being;4 He is eternal,5 incomprehensible,6 invisible,7 unchangeable,8 infinite,9 almighty,10 completely wise,11 just,12 good,13 and the overflowing source of all good.14
Bible References: 1Rom. 10:10 2Deut. 6:4; 1 Cor. 8:4,6; 1 Tim. 2:5 3Simple means God is not composed of parts; He is pure spirit without division or complexity 4John 4:24 5Ps. 90:2; 1 Tim. 1:17 6Rom. 11:33 7Col. 1:15; 1 Tim. 6:16 8James 1:17; Mal. 3:6 91 Kings 8:27; Jer. 23:24 10Gen. 17:1; Matt. 19:26; Rev. 1:8 11Rom. 16:27 12Rom. 3:25,26; 9:14; Rev. 16:5,7 13Matt. 19:17 14James 1:17
The Belgic Confession of Faith (1561) - Article 1