I’ve never been in court and in need of defense, but if I were, I would want those closest to me, whom I trusted, to be at my side as witnesses. But I have stood in God’s court, having transgressed His law. I praise God that Jesus took my place as the accused and granted me His obedience to the law so that God now views me as positively righteous. Despite that glorious truth, the world, the flesh, and the devil constantly haul me before their kangaroo courts to bear witness against me that I live inconsistently with who I am in Christ, that my deepest thoughts are vile, and that I deserve eternal condemnation.
Who stands up constantly against these accusers and bears witness for me—and you? Of course, the Lord Jesus Christ does (1 John 2:1). In Romans 8:16, though, Paul says, “The Spirit himself bears witness,” meaning that there is a special witness of the Holy Spirit to assure us that we are the children of God. He bears witness “with our spirit,” that we are forgiven, though our spirits are constantly plagued with a sinful nature as well as daily sins we all know so well. As one poet said:
But ah! too soon my fears return.
And dark mistrust disturbs anew:
What smothered fires within yet burn!
My days of peace, alas, how few!
These heart-throes,—shall they ne’er
These strifes,—shall they for ever last?
If you are at all acquainted with yourself, you know that faith is a struggle and that not all believers feel assured in the same way at all times. Romans 8:16 is important because it teaches us that while faith includes an implicit assurance, that assurance is not always explicitly felt. This is where the Spirit works to advocate and bear witness that we are children of God. And this statement comes after a progression in verses 13–16. Those who mortify sin have been given new life. How do we know that? The Spirit leads us as sons of God. Why? Because we did not receive a Spirit of fear but the Spirit of adoption, causing the cry, “Abba! Father!” Even more, the Spirit himself bears witness that we are children of God.
But notice something about verses 15 and 16. Who is crying out in verse 15? “By whom we cry.” Our own adopted soul witnesses that we are sons of God. Verse 16 adds to this the witness of Spirit. And Paul uses this verb—bears witness with—in two other places in Romans to speak of a twofold witness (2:15; 9:1). Why is this important to see? Paul is saying that we are not left to ourselves to figure out if we are God’s children. He has poured out His love into our hearts through the Holy Spirit, who was given to us (Rom. 5:5). The Holy Spirit, then, testifies by our spirit when we cry out, “Father!” (8:15) and He also testifies to our spirit that we are children of God (v. 16). The Spirit assures us by our own spirits as well assuring our spirits by His own testimony.