'Witness' in the Bible

But God is my witness that it was in pity for you that I did not come to Corinth at that time.

Now he who has made us for this very thing is God, who has given us the Spirit as a witness of what is to come.

For I give them witness, that as they were able, and even more than they were able, they gave from the impulse of their hearts,

The God and Father of our Lord Jesus Christ, to whom be praise for ever, is witness that the things which I say are true.