'God is Witness' in the Bible

If thou shalt afflict my daughters, and if thou shalt take wives besides my daughters, no man is with us; see, God is witness betwixt me and thee.

Now God is witness that the things which I am writing to you are true.

For neither at any time were we found using words of flattery, as ye know, nor a cloak of covetousness, God is witness;

You yourselves are witnesses--and God is witness--how holy and upright and blameless our dealings with you believers were.