Why Do You Believe
...the only reason why we do believe that Jesus Christ is the Son of God, that God is one single essence subsisting in three persons, is because that God who is truth, the “God of truth,” Deut. 32:4, who “cannot lie,” Tit. 1:2, and whose “word is truth,” John 17:17, and the Spirit which gave it out is “truth,” 1 John 5:6, hath revealed these things to be so.
John Owen, The Reasons of Faith, The Works of John Owen, ed. William H. Goold, vol. 4 (Edinburgh: T&T Clark, 1677), 18.