The Endurance of Ideas

Seu bona seu mala sint, durant concepta per usum.
Quam flectis virgam, ventis invicta fit arbor.    

Good or bad, thought habits endure through practice.  
You bend a branch which becomes a tree, impervious to the winds.

Notes:
Sextus Amarcius (Fl. 11th c.), Sermonum libri IV, ed. by Maximilianus Manitius (Leipzig: Teubner, 1888), p.46 [Sermo III.36-37]. My translation.