“And hereby we do know that we know him, if we keep his commandments.”
King James Version (KJV)
2:3 And hereby we know that we truly and savingly know him - As he is the advocate, the righteous, the propitiation. If we keep his commandments - Particularly those of faith and love.
1Jo 2:3 And by this we do know that we know him. The evidences that we have a saving knowledge of Christ is loyal obedience to his commandments.