We become what we love, and what we love shapes what we become.
Attr. St. Clare of Assisi
This came in low enough on my “sounds right” test to get me searching. The first search result was from Goodreads, which means no citation.
The second hit was from a blog by a teacher at Franciscan University of Steubenville, who gave a longer version: “We become what we love and who we love shapes what we become. Imitation is not a literal mimicking of Christ; rather, it means become the image of the beloved, an image disclosed through transformation.” The author attributed that to St. Clare, but it scores about as low as it is possible to score on my “sounds right” scale, so I searched for the second sentence, and it turned up very quickly in Google Books, in a book called Franciscans at Prayer, by Timothy Johnson, p. 54. You can see that page here. The words–all of them–are Johnson’s, not St. Clare’s.
They didn't say it 