Children should be taught that if they are selfish and live just for themselves they will become isolated from others and finish up by being lonely and miserable - which amounts to a hell on earth. In other words they should do their best to love others as they love themselves. They will indeed be tormented as the result of their own pride, vanity, greed, arrogance, impatience, cynicism, scepticism and lust for power.
Indeed. The beauty of Christ’s teaching is that it strikes a balance between self-interest and altruism. On the one hand He tells us that we should love our neighbour as ourselves (i.e. neither more nor less) and on the other that there is no greater love than to give our life for our friends. The apparent conflict is resolved by the fact that the norm is transcended by self-sacrifice
in this life - which is where the Beatitudes are relevant. Divine justice ensures that ultimately we all obtain precisely what we deserve but divine love gives us far more than that: life in heaven if our love is greater than simply fulfilling our obligations. Jesus died for everyone, not only Christians but
all those who respond to His love regardless of what they claim to believe or disbelieve:
And for these sheep I am laying down my life. I have other sheep too, which do not belong to this fold ; I must bring them in too ; they will listen to my voice ; so there will be one fold, and one shepherd."
John x. 11-16