Westminster Larger Catechism - Question 9

How many persons are there in the Godhead?

There be three persons in the Godhead, the Father, the Son, and the Holy Ghost; and these three are one true, eternal God, the same in substance, equal in power and glory; although distinguished by their personal properties. ^a

^a I John 5:7; Matt. 3:16-17; 28:19; II Cor. 13:14; John 10:30