This is how we are sure that we have come to know Him: by keeping His commands.
References for 1 John 2:3
The one who says, "I have come to know Him," without keeping His commands, is a liar, and the truth is not in him.
But whoever keeps His word, truly in him the love of God is perfected. This is how we know we are in Him:
References for 1 John 2:5
the one who says he remains in Him should walk just as He walked.