‘It’s not fair.’ We are born with an innate of sense of fairness. There’s no way to annoy a child more than to frustrate this sense of fairness. We know jealousy is a sin. In the Old Testament, we’re instructed against jealousy: ‘Thou shalt not covet thy neighbour's house, thou shalt not covet thy neighbour's wife, nor his manservant, nor his maidservant, nor his ox, nor his ass, nor any thing that is thy neighbour’s.’ (Exod 20.17). Don’t be jealous. […]