Mark 12:30–31: Does a Christian Love Himself?
Jesus names wholehearted love for God as the greatest commandment and neighbor-love as its twin. The command never asks you to manufacture love for yourself; it turns the care you already give your own interests toward the person beside you.
John 15:9–11: Where Christian Joy Comes From
Jesus does not hand his disciples a mood to manufacture but a person to remain in. In John 15:9–11 he grounds joy in his own love and in obedience that keeps us there.
John 15:11: Where Joy Comes From
Jesus does not offer his disciples a joy they must manufacture. He speaks so that his joy may remain in them and their joy may be made full, which means joy flows from remaining in his love.
What Does 1 John 4:19 Mean? Context, Theology, and Application
1 John 4:19 teaches that genuine Christian love begins not in human willpower but in God's prior, saving love revealed through Jesus Christ.