'Witness' in the Bible

For God, whom I serve in my spirit in the preaching of the gospel of His Son, is my witness as to how unceasingly I make mention of you,

in that they show the work of the Law written in their hearts, their conscience bearing witness and their thoughts alternately accusing or else defending them,

The Spirit Himself testifies with our spirit that we are children of God,

I am telling the truth in Christ, I am not lying, my conscience testifies with me in the Holy Spirit,

For I testify about them that they have a zeal for God, but not in accordance with knowledge.