1 John 5:10

1 John 5:10. He that believeth on the Son of God hath the witness in himself. The testimony has become subjective: the ‘three agree in one' within the believer's consciousness. He has for we must anticipate 1 John 5:11 eternal life within him: the gift of the Spirit of life received by Christ for us at His baptism, the forgiveness of sin or release from the condemnation of death through His blood, and the Holy Ghost effecting and assuring both. Faith is followed by full assurance; but the assurance is here the possession of life itself.

But he that believeth not God hath made him a liar: because he hath not believed the witness that God hath borne concerning His Son. He is not only without the internal testimony, but he has also rejected the external testimony, which has been given to one who hears the Gospel record so abundantly that he is without excuse. Once before St. John had spoken of making God a liar: he who denies that he has sinned is a liar himself, and contradicts the express testimonies of God. Similarly, he who believes not the witness given by God concerning His Son rejects the utmost possible evidence that God, knowing man's necessity, could give him. It is supposed that he has the evidence before him, and that in the form of spoken or written evidence; it is further supposed that he deliberately rejects the testimony, knowing it to be Divine. There is nothing stronger, scarcely anything so strong, in all the Scriptures, concerning the moral wilfulness of unbelief. It is not said that he who refuses to accept the testimony to the divinity and incarnation of the Son loses the benefit; nor simply that he blinds his own mind; but that he hears the voice of God and makes Him a liar. Nor are the last words, as has been thought by some, mere vehement repetition. God is made a liar by the man who rejects the eternal life which has been once for all given. The witness rejected is not this or that saying or miraculous demonstration, but the whole strain of proof brought by the Christian revelation that both light and life are come into the world as the heritage of every man who does not wilfully reject both.