Love the sinner, but hate the sin.
But it is frequently used by christians an excuse to declare how sinful the 'lifestyle choices' of others are.
"I love you, but you're going to hell." "I'm only telling you how sinful you are because I love you."
I do not believe that anyone has ever felt loved by that! And I've certainly never seen anyone change their behaviour because they were told how much their sin was hated.
But the bible does tell us that God's kindness leads us to repentance. So maybe we can leave it up to him to deal with other people's sin. Just maybe that's his business, not ours.
All Jesus told us to do was love our neighbour as much as we love ourselves. Not to go around pointing out their sins. Just to love them.
And last time I looked, we weren't doing that very well! So maybe we can concentrate on practicing what we have been told to do, and let the instructions we've added fall to the wayside.