A.T. Robertson Commentary 1 Corinthians 14:25

"the secrets of his heart are made manifest; and so he will fall down on his face and worship God, declaring that God is among you indeed." — 1 Corinthians 14:25 (ASV)

That God is among you indeed (οτ οντως εν υμιν εστιν). Recitative οτ and direct quotation from Isa 45:15 (Hebrew rather than the LXX). "Really (οντωςLuke 24:34) God is in you."