In Scripture, the number of divine fullness, resurrection, and witness. Father, Son, and Holy Spirit constitute the Triune God; Jonah was three days in the fish, Christ three days in the tomb; the seraphim cry Holy, Holy, Holy threefold; the high priest wears three-part garments; Peter denies thrice and is restored thrice; the Lord appears three times in the Acts witness pattern of 1 John 5.
THREE, a.
Two and one. In scripture, the number three is often a symbol of completeness, divine fullness, and the Triune God.
Isaiah 6:3 — "Holy, holy, holy, is the Lord of hosts."
Matthew 28:19 — "Baptizing them in the name of the Father, and of the Son, and of the Holy Ghost."
Jonah 1:17 — "Jonah was in the belly of the fish three days and three nights."
1 John 5:7 — "There are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one."
Modern theology sometimes flattens the Trinity; Scripture writes it in threes from Genesis to Revelation.
The number three runs through Scripture as the signature of the Triune God. Father, Son, and Holy Spirit speak at the baptism of Christ. The seraphim sing Holy three times before the throne. The blessing of Numbers 6 names the Lord three times: the Lord bless thee... the Lord make his face shine upon thee... the Lord lift up his countenance upon thee. The Great Commission baptizes in the threefold name.
Modal heresies ancient and modern try to flatten the three into one without distinction. The Bible refuses. The three are one in essence; the three are distinct in Person; both truths stand. Worship the Triune God exactly as He has revealed Himself — not as a single Person playing three roles, not as three Gods, but as one God in three Persons. The threefold structure of the Bible itself testifies to the doctrine.
Hebrew shalosh (H7969); Greek treis (G5140).
H7969 — shalosh — three
G5140 — treis — three
"The Bible is written in threes from Genesis to Revelation; the Triune God signs His own work."
"Modal heresies flatten the three into one; the Bible refuses the flattening."
"Three in one, one in three — both halves of the doctrine stand."