Have Ye Not Read?
Question: Please explain Romans 8.16, the witness of the spirits. What is our spirit (human spirit)?
Reply: Paul wrote, "The Spirit himself beareth witness with our spirit, that we are children of God (Rom. 8:16).
In the previous verses (vv. 14,15), Paul has discussed sonship. "For as many as are led by the Spirit of God, these are sons of God" (v. 14). The Holy Spirit teaches us how to live, and does so through the medium of the word of God. He leads children of God through the power of the gospel. So, by divine revelation, we are taught how to live before God. The same Spirit of God (the Holy Spirit) teaches men and women to become children of God, thus leading them to the truth. The gospel is the power of God unto salvation (Rom. 1: 16), but the Spirit leads through the gospel. Then in the next verse we are told, "For ye received not the spirit of bondage again unto fear; but ye received the spirit of adoption whereby we cry, Abba, Father" (v. 15). Having stated that the Spirit of God leads us, this done through divine revelation, Paul then refers to the spirit which we receive; that it is the spirit of adoption (or sonship) and that it is not the spirit of bondage unto fear. The Jews who had lived under the old law lived mainly by fear. Before Paul's readers were converted they had been moved by fear. This is not true of the Christian. Children of God have a different kind of spirit. This being the case, we are led to the conclusion that the spirit received by the child of God pertains to an attitude rather than intelligence. Instead of a spirit of fear, children of God possess a spirit of sonship, a recognition of and a trust and reverence for the Heavenly Father (see Matt. 7:11).
Our spirit (v. 16), in view of the sonship that Paul has just discussed, is a disposition or attitude. We are children who serve God in the spirit of love and obedience to His will. The Holy Spirit testifies as to how we are to live as children of God, and by following His instructions in the Scriptures, we serve God in the spirit of love and obedience. These are the witnesses of the spirits - the Holy Spirit and our spirit. God has given to us the spirit of children; so we serve as such, and not as slaves. This meaning conforms to the context of the passage; therefore, we believe it to be the plausible explanation.
Guardian of Truth XXVIII: 16, p. 485