If the term “Trinity” is not found in the Bible, then why do Christians believe in God’s tri-unity? Here is my attempt to answer that question in 200 words or less. (Note that I did not include Scripture references in my word count.)Although the term Trinity does not occur in Scripture, the concept is inherently biblical. The Trinitarian nature of God was revealed implicitly in the Old Testament and explicitly in the New Testament.The doctrine of the Trinity is founded on two fundamental theological realities: (1) There is one true God. (2) The one God has eternally existed as three distinct Persons, each of whom is equally and fully God. Reality 1: Scripture teaches that there is one true God (cf. Deut. 4:35; 6:4; Isa. 43:10–11; 45:5, 18, 21–22; 46:9; Joel 2:27; Zech. 14:9; Mal. 2:10; Mark 12:29; James 2:19; 1 Tim. 2:5).Reality 2: Scripture also teaches that God has eternally existed as three distinct Persons, each of whom is equally and fully God.A. The Father is God (cf. Matt. 6:9, 14; John 17:1–3; 1 Cor. 8:6; 2 Cor. 1:3; Php. 2:11; Col. 1:3; 1 Pet. 1:2).B. The Son is God (cf. Isaiah 9:6; Matt. 1:23; John 1:1, 14, 18; 20:28; Acts 20:28; Rom. 9:5; 1 Cor. 1:24; 2 Cor. 4:4; Php. 2:6, 10–11; Col. 1:15–16; 2:9; Titus 2:13; Heb. 1:3, 8; 2 Pet. 1:1; 1 John 5:20).C. The Son is distinct from the Father (Matt. 11:27; John 1:1–2; 3:35; 4:34; 5:30–32, 37; 6:38; 10:36; 12:49; 14:8–11; 17:20–24; Gal. 4:41 John 2:1; Heb. 7:25).D. The Holy Spirit is God (Gen. 1:2; 6:3; Job 33:4; Psalm 139:7–8; John 3:3–8; 14:23; Acts 5:3–4; 1 Cor. 2:10–11; 6:16,19;  2 Cor. 3:18; Heb. 9:14; 10:15–16; 2 Thess. 2:13; 1 Pet. 1:10–11; 2 Pet. 1:21). Moreover, the Holy Spirit is a person, possessing the attributes of personhood (Mark 3:29; John 14:26; 16:8; Acts 8:29; 13:2; 16:6; Rom. 8:26; 15:30; 1 Cor. 12:11; Eph. 4:30; 1 Tim. 4:1; Heb. 10:29; Rev. 2:7).E. The Spirit is distinct from the Father and the Son (Isaiah 48:16; Matt. 28:19; Luke 3:21; John 14:16–17; 26; 16:13–14; Rom. 8:27; Heb. 9:8).On this basis, the Bible often refers to God in ways that emphasize all three Members of the Trinity (Matt. 28:19; Rom. 14:17–18; 15:13–17; 15:30; 1 Cor. 6:11, 17–19; 12:4–6; 2 Cor. 1:21–22; 3:4–6; 13:14; Gal. 2:21–3:2; Eph. 2:18; 21–22;  3:11–17; 4:4–6; 5:18–20; Php. 2:1, 6; Col. 1:6–8; 1 Thess. 1:1–5; 4:2, 8; 5:18–19; 2 Thess. 2:13, 14; 3:5; Titus 3:4–6; Heb. 9:14; 1 John 3:23–24; Jude 20–21).Thus, we embrace the truth of the Trinity because God has revealed Himself in this way in His Word.