You shall know them by their fruit

Matthew 7:15–20 (ASV)

¹⁵Beware of false prophets, who come to you in sheep’s clothing, but inwardly are ravening wolves. ¹⁶By their fruits ye shall know them. Do men gather grapes of thorns, or figs of thistles? ¹⁷Even so every good tree bringeth forth good fruit; but the corrupt tree bringeth forth evil fruit. ¹⁸A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. ¹⁹Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. <...

John 13:34–35 (ASV)

³⁴A new commandment I give unto you, that ye love one another; even as I have loved you, that ye also love one another. ³⁵By this shall all men know that ye are my disciples, if ye have love one to another.

John 15:8 (ASV)

⁸Herein is my Father glorified, that ye bear much fruit; and so shall ye be my disciples.

Galatians 5:22–23 (ASV)

²²But the fruit of the Spirit is love, joy, peace, longsuffering, kindness, goodness, faithfulness, ²³meekness, self-control; against such there is no law.