Thomas Aquinas Quotes about Sin
Thomas Aquinas (2013). “Summa Theologica (All Complete & Unabridged 3 Parts + Supplement & Appendix + interactive links and annotations)”, p.2852, e-artnow
Venial sin becomes mortal sin when one approves it as an end. . .
Thomas Aquinas (2003). “On Evil”, p.273, Oxford University Press
Sin is a spiritual illness; thus sinners are in need of salvation.
Saint Thomas (Aquinas) (2010). “The Academic Sermons (The Fathers of the Church, Mediaeval Continuation, Volume 11)”, p.47, CUA Press
It must be said that charity can, in no way, exist along with mortal sin.
"Quaestiones disputatae: De caritate (Disputed Questions: On Charity)". Book by Thomas Aquinas, circa 1270.
St Thomas Aquinas (2013). “Summa Theologica, Volume 3 (Part II, Second Section)”, p.1680, Cosimo, Inc.