Orthodox Catechism, Q. 24
Deuteronomy 6:4 ASV, Psalm 110:1 ASV, Isaiah 44:6 ASV, Isaiah 45:5 ASV, Isaiah 61:1 ASV, Matthew 3:16-17 ASV, Luke 4:18 ASV, John 14:26 ASV, John 15:26 ASV, 1 Corinthians 8:4 ASV, 2 Corinthians 13:14 ASV, Galatians 4:6 ASV, Ephesians 2:18 ASV, Ephesians 4:6 ASV, Titus 3:3-6 ASV and 1 John 5:7 ASV
Q. 24. Seeing (d) there is but one only substance of God, why namest thou those three, the Father, the Son, and the Holy Ghost?A. Because God (e) hath manifested himself in his Word, that these three distinct Persons are that one true everlasting God.
(a) Deut. 6.4. Eph. 4.6. Isa. 44.6 and 45.5. 1 Cor. 8.4.
(b) Isa. 61.1. Luk. 4.18. Ps.110.1. Mat. 3.16, 17 and 28.19. John 14.26 and 15.26. Tit. 3.5, 6. Ephes. 2.18. 2 Cor 13.14. Gal. 4.6. 1 John 5.7.