The Spirit itself bears witness with our spirit, that we are the children of God:
It is the high and distinguishing privilege of true Christians that they are the children of God; but there is a wide difference between possessing a privilege and knowing that we possess it. A man may have in law a clear title to an estate without feeling sure in his own mind that he has such a title. He may possess a real interest in some very beneficial concern, and yet may be ignorant of his claim, or perhaps have considerable doubts as to the justice of his pretensions. The text discloses the way by which the true Christian may attain to a strong and lively hope of his adoption — namely, through the testimony of the Spirit. What, then, is this witness of the Spirit?
I. IT IS A PRIVILEGE WHICH THE SPIRIT OF GOD FREELY BESTOWS; which He confers or withholds as He sees fit. Some may wait many years before they are favoured with it, and may afterwards lose it. Nor is the Spirit less free as to the degree of the testimony. To one He bears a weaker, to another a stronger witness.
II. IT IS A SECRET INWARD OPERATION of the Holy Ghost "with our spirit." Consequently it can be known only to the person to whom it is given. By his fruits others know him.
III. IT PERFECTLY AGREES WITH THE WRITTEN WORD OF GOD; for the Spirit cannot contradict Himself — e.g., should a person pretend to have it whose life exhibited none of those marks with which Scripture distinguishes the children of God, it would be plain that he was mistaken in his pretensions. For could the Spirit witness to him a falsehood?
IV. IT HAS NOTHING TO DO WITH SUDDEN AND VIOLENT IMPULSES, new revelations, sensible impressions, etc. Let us not deny or overlook the real operations of the Spirit of God; but let us not blaspheme Him, nor bring them into contempt, by ascribing to His agency effects which are proofs of nothing but of error, weakness, or imposture.
V. WHEREVER THE SPIRIT BEARS WITNESS TO THE ADOPTION OF SONS, THERE HE HAS BEEN FIRST RECEIVED AS THE SPIRIT OF ADOPTION (ver. 15).
Parallel VersesKJV: The Spirit itself beareth witness with our spirit, that we are the children of God: