Assurance: The believer’s assurance of salvation[1], that he belongs to the truth (3:19), has two bases: the Savior and His Spirit. First, it is the Savior. It is the Son of God, the Lord Jesus Christ in whom we have placed our trust. What guarantees our salvation is not the strength of our faith but the strength of the Savior in whom we trust. Christ is mighty to save, therefore, all who trust in Him are unquestionably saved. Now, John’s focus in this passage is not on this first basis of assurance but the second, which is the Holy Spirit, the reference with which he concludes this section (3:24). The Holy Spirit is real, as much as God is real. He is the third person of the triune God. And He always leaves His unmistakable mark on believers. They are transformed.[2] Those in whom the Spirit dwells are led by Him (Rom. 8:14), they put to death the deeds of the flesh (Rom. 8:12-13), and they manifest the fruit of the Spirit (Gal. 5:22-23).

Love and Obedience: John gives us at least two evidences of the Spirit’s presence: love for God’s people (3:23) and obedience to His word (2:3-4; 3:22-23). John already highlighted the first of these in 3:17-18. Without practical and tangible display of love, no one can say the love of God is in him. Though he may say “I believe,” he is still in the darkness and has no fellowship with God (2:10; 1:6-7). It’s the same with obedience. If a person refuses to put Scripture into practice, the verdict is unbelief. Unbelief is undeniably practical. Obedience is costly, and unbelievers do not pay the price. John also mentions this evidence: God’s ears are open to the prayers of His children (3:22).[3]

[1] John begins and ends with the certainty (“we know”) about our identity in Christ (3:19 and 3:24).

[2] All believers are born of the Spirit (John 3:5-6). The Spirit’s transforming work is visible in them (John 3:8).

[3] This (echoed in 5:14-15) reverberates throughout Scripture: Psalm 34:15; 37:4; 145:18; Prov. 15:8, 29; 28:9.