"For the truth's sake, which dwelleth in us, and shall be with us for ever." (2 John 2)
The word "truth" occurs more in the gospel of John than in any other book of the New Testament, and it occurs in the first epistle of John more than in any other book except John's gospel. Then, it occurs more in John's two one-chapter epistles (2 and 3 John) than in any other New Testament book save John and 1 John. Surely one of the great themes in John's writings is truth!
God is, indeed, the God of truth, and His written Word is "the scripture of truth" (Daniel 10:21). "For the word of the LORD is right; and all his works are done in truth" (Psalm 33:4). The Lord Jesus Christ is, in fact, the very incarnation of truth. "I am the way, the truth, and the life," He asserted (John 14:6).
Surely truth dwells forever in Christ, for He is Himself the Creator and is thereby the very definition of truth. But how can it be that truth dwells in us and shall be with us forever? This is certainly not the case with the natural man.
It can only be by the Holy Spirit, of course, and this is what Christ—who is the truth—has promised. "And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever; Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you" (John 14:16-17).
That being so, with the Holy Spirit of truth indwelling us forever, our words, and deeds, and our very lives should be characterized by truth and complete consistency. "Wherefore putting away lying, speak every man truth with his neighbor" (Ephesians 4:25). "If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth" (1 John 1:6). HMM