The 1689 London Baptist Confession of Faith:
3. In this divine and infinite Being there are three
subsistences, the Father, the Word or Son, and Holy Spirit,27
of one substance, power, and eternity, each having the whole divine
essence, yet the essence undivided:28 the Father is of
none, neither begotten nor proceeding; the Son is eternally begotten
of the Father;29 the Holy Spirit proceeding from the Father
and the Son;30 all infinite, without beginning, therefore
but one God, who is not to be divided in nature and being, but
distinguished by several peculiar relative properties and personal
relations; which doctrine of the Trinity is the foundation of all our
communion with God, and comfortable dependence on Him.
(27. 1 Jn 5:7; Mat 28:19; 2 Cor 13:14 28. Exod 3:14; Jn 14:11; 1 Cor
8:6 29. Jn 1:14,18 30. Jn 15:26; Gal. 4:6)