“ Now concupiscence is a distinct passion from love, as stated above (Q. 3, A. 2; Q. 23, A. 4). Therefore self-love is not the cause of every sin. ”
 Thomas Aquinas, Summa Theologica (1274). copy citation

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“7:8) : "Sin taking occasion by the commandment wrought in me all manner of concupiscence"; on which words a gloss says that "the law is good, since by forbidding concupiscence, it forbids all evils," the reason for which is that concupiscence is the cause of every sin. Now concupiscence is a distinct passion from love, as stated above (Q. 3, A. 2; Q. 23, A. 4). Therefore self-love is not the cause of every sin. Obj. 3: Further, Augustine in commenting on Ps. 79:17, "Things set on fire and dug down," says that "every sin is due either to love arousing us to undue ardor or to fear inducing false humility." Therefore self-love is not the only cause of sin.
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