Catena Aurea on Matthew 5:43–48: Augustine of Hippo

But as we laud Him for His gifts, let us also consider how He chastises those whom He loves. For not every one who spares is a friend, nor every one who chastises an enemy; it is better to love with severity, than to use lenity wherewith to deceive [margin note: see Prov. 27:6].