Lewis now turns to the first “theological” virtue: charity. Charity is often taken to mean giving to the poor, but it is more than this; in fact, it encompasses something Lewis has already discussed—namely, forgiveness and, more broadly, love for one’s neighbor. As he previously noted, this does not require feelings of affection, though Lewis does warn against charity undertaken in an attempt to put another individual in our debt.

Although Christian charity is not sentimental by nature, and there are cases where feelings of affection can actually impede our ability to treat someone charitably (e.g. spoiling a child to their moral detriment). Generally speaking, however, treating someone charitably will often result in increased affection for them. In this sense, Lewis likens both love and hatred to “compound interest” (132), suggesting that whichever we practice tends to multiply upon itself. Lewis notes that these same precepts also apply to the Christian injunction to love God: “Do not sit trying to manufacture feelings. Ask yourself, ‘If I were sure that I loved god, what would I do?’ When you have found the answer, go and do it” (132).

Lewis suggests that God’s love for us is more stable than our love for Him.