'Liar' in the Bible

You are of your father the devil, and it is your will to practice the desires [which are characteristic] of your father. He was a murderer from the beginning, and does not stand in the truth because there is no truth in him. When he lies, he speaks what is natural to him, for he is a liar and the father of lies and half-truths.

Yet you do not know Him, but I know Him fully. If I said I did not know Him, I would be a liar like you. But I do know Him and keep His word.

Certainly not! Let God be found true [as He will be], though every person be found a liar, just as it is written [in Scripture],“That You may be justified in Your words,And prevail when You are judged [by sinful men].”

If we say that we have not sinned [refusing to admit acts of sin], we make Him [out to be] a liar [by contradicting Him] and His word is not in us.

Whoever says, “I have come to know Him,” but does not habitually keep [focused on His precepts and obey] His commandments (teachings), is a liar, and the truth [of the divine word] is not in him.

Who is the liar but the one who denies that Jesus is the Christ (the Messiah, the Anointed)? This is the antichrist [the enemy and antagonist of Christ], the one who denies and consistently refuses to acknowledge the Father and the Son.

If anyone says, “I love God,” and hates (works against) his [Christian] brother he is a liar; for the one who does not love his brother whom he has seen, cannot love God whom he has not seen.

The one who believes in the Son of God [who adheres to, trusts in, and relies confidently on Him as Savior] has the testimony within himself [because he can speak authoritatively about Christ from his own personal experience]. The one who does not believe God [in this way] has made Him [out to be] a liar, because he has not believed in the evidence that God has given regarding His Son.