Therefore love is not a wounding passion, but rather one that preserves and perfects.
 Thomas Aquinas, Summa Theologica (1274). copy citation

add
Author Thomas Aquinas
Source Summa Theologica
Topic passion love
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17897/pg17897-images.html

Context

“Hier. vii) in reckoning the properties belonging to the Seraphim's love, includes "hot" and "piercing" and "most fervent." Moreover it is said of love (Cant 8:6) that "its lamps are fire and flames." Therefore love is a wounding and corruptive passion.
On the contrary, Dionysius says (Div. Nom. iv) that "everything loves itself with a love that holds it together," i.e. that preserves it. Therefore love is not a wounding passion, but rather one that preserves and perfects. I answer that, As stated above (Q. 26, AA. 1, 2; Q. 27, A. 1) , love denotes a certain adapting of the appetitive power to some good. Now nothing is hurt by being adapted to that which is suitable to it; rather, if possible, it is perfected and bettered.” source