New International Version
Whoever says, "I know him," but does not do what he commands is a liar, and the truth is not in that person.

American Standard Version
He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him;

Berean Study Bible
If anyone says, “I know Him,” but does not keep His commandments, he is a liar, and the truth is not in him.

Douay-Rheims Bible
He who saith that he knoweth him, and keepeth not his commandments, is a liar, and the truth is not in him.

English Revised Version
He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him:

King James Bible
He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.

World English Bible
One who says, "I know him," and doesn't keep his commandments, is a liar, and the truth isn't in him.

Young's Literal Translation
he who is saying, 'I have known him,' and his command is not keeping, a liar he is, and in him the truth is not;

1 John 2:4 Additional Translations ...