"The way we may be sure that we know the Lord is to keep his commandments. Whoever says, 'I know him,' but does not keep his commandments is a liar, and the truth is not in him. But whoever keeps his word, the love of God is truly perfected in him. This is the way we may know that we are in union with him: whoever claims to abide in him ought to walk just as he walked."
1 John 2:3-6