For as many as are led by the Spirit of God, these are sons of God. For you did not receive the spirit of bondage again to fear, but you received the Spirit of adoption by whom we cry out “Abba, Father.” The Spirit Himself bears witness with our spirit that we are children of God. (Romans 8:14–16—NKJV)

There are many tangible proofs by which a man knows that he has eternal life. God never intended that the redemption work of His Son would be an “iffy” proposition. His intention, execution, procurement, and application of His great redeeming act is accomplished with absolute certainty and with absolute precision. It is for this reason that receiving salvation is synonymous with eternal life and eternal security. John 20:31 states, “These things are written that you may believe that Jesus is the Christ, the Son of God, and that believing you may have life in His Name.” 1 John 5:13 underscores this same truth: “These things I have written to you who believe in the Name of the Son of God, that you may know that you have eternal life, and that you may continue to believe in the Name of the Son of God.” It cannot be eternal life if it can be lost, just as it cannot be a gift if it can be earned. Salvation is a complete package and its granting and gifting is irreversible.

By the same token, precisely because salvation is a gift, a man is bound to search out the reality of his reception of the gift of eternal life (2 Peter 1:10). Salvation is not given in response to works of righteousness which a man can do (Ephesians 2:8–10), nor is it granted because of some sort of spiritual pedigree or worthiness (Philippians 3:1–9). Salvation does not come from within the penitent heart but from above (John 3:3, James 1:17), and therefore a man must be convinced of the reality of his salvation by something, or rather Someone, outside of himself, as our text states. No mere, fallible man will do to satisfy a man’s need to know for sure.

Since salvation is by faith in the stated promise of God (John 3:16–18, Romans 10:9–13), God is not obligated to provide further assurance to His children than simply to give His Word. It is out of His gracious lovingkindness that He places His Spirit within each of His children (Ephesians 1:13–14, 5:18) and, through His ministrations, assures every individual believer of the authenticity of his sonship. Verse 14 points out that being led by the Spirit of God is one evidence of eternal life. His work is to lead as a teacher leads a student to understanding and knowledge. The believer’s response to this leading is to fill his day with Spirit-led decisions.

The Holy Spirit has a specific task, and that is (as the Lord predicted to the Apostles), “He will guide you into all truth; for He will not speak on His Own authority, but whatever He hears He will speak; and He will tell you things to come. He will glorify Me, for He will take of what is Mine and declare it to you” (John 16:13–14). The Holy Spirit works through the Word. The Holy Spirit is the Comforter (Helper) sent to indwell believers and to “convict the world of sin, and of righteousness, and of judgment” (John 16:7–11). 1 Corinthians 2:12 speaks of the Holy Spirit’s work of illumining the heart of believers: “Now we have received, not the spirit of the world, but the Spirit who is from God, that we might know the things that have been freely given to us by God.” Romans 8:15 teaches that the indwelling Holy Spirit is the Spirit of adoption by whose prompting release we “loudly cry out” (with strong, deep conviction and emotion) unto our Father (the same term as used by our Lord in Gethsemane). See Galatians 4:6–7.

The Holy Spirit’s work is further described as “bearing joint witness” with our spirit (the spirit is that part of us energized by the Holy Spirit). Joint witness means that there are two individuals whose testimonies match, having seen the same thing they testify to the same recounting of the facts in full unison and harmony. Romans 8:23 refers to His testifying within us as “firstfruits of the Spirit.” Sin disrupts this work of the Holy Spirit as 1 John 3:24 teaches, “Now he who keeps His commandments abides in Him, and He in him. And by this we know that He abides in us by the Spirit whom He has given us.” This truth is reiterated in 4:13, “By this we know that we abide in Him, and He in us, because He has given us of His Spirit.” Finally, 5:6 reads, “This is He who came by water and blood—Jesus Christ, not only by water, but by water and blood. And it is the Spirit who bears witness, because the Spirit is truth.”

This confirming and affirming work of the Spirit of God is a gracious gift of assurance within every faithful believer that demonstrates the authenticity of the believer’s faith in the promises of God. Do you have this conviction and confirmation unmistakably from no other source but the Holy Spirit? If so, thank Him for bearing joint witness. If not, do not rest until you have been granted this blessed assurance by God. Trust and obey.