True.
And neither should we sin against those who have no faith whatsoever. Including those that think they are secure but are not.
KR
True, I've seen many claims on the RF to "know Jesus" and "all sins, past, present, or future" are forgiven no matter what they do and regard those comments as a false sense of security. Beyond doubt, the Lord knows our works (He said so) and warns against people thinking they know Him (but their works are evil; they don't keep His commandments). Yet love covers a multitude of sins and we are called to love, to be saints, to walk worthy of His calling, though we all fall short.