3 John 9-12, KJV
9I wrote unto the church: but Diotrephes, who loveth to have the preeminence among them, receiveth us not.10Wherefore, if I come, I will remember his deeds which he doeth, prating against us with malicious words: and not content therewith, neither doth he himself receive the brethren, and forbiddeth them that would, and casteth them out of the church.11Beloved, follow not that which is evil, but that which is good. He that doeth good is of God: but he that doeth evil hath not seen God.12Demetrius hath good report of all men, and of the truth itself: yea, and we also bear record; and ye know that our record is true.
We are to imitate good. Those of us who practice goodness are of God—walking after the Holy Spirit. The Spirit will not tell us to do anything that does not bring glory to Him. “Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven,” Matthew 5:16, KJV. But those who make it a practice of doing evil does not know God. “Wherefore by their fruits ye shall know them,” Matthew 7:20, KJV.
Additional Reading: 3 John 1-14