Similitudo, proprie loquendo, est causa amoris quia in amore concupiscentiae amans proprie amat seipsum, cum vult illud bonum quod concupiscit.
Likeness, properly speaking, is a cause of love, because in the love of concupiscence, the lover, properly speaking, loves himself, in willing the good that he desires.
Magis autem unusquisque seipsum amat quam alium, quia sibi unus est in substantia, alteri vero in similitudine alicuius formae. Et ideo si ex eo quod est sibi similis in participatione formae, impediatur ipsemet a consecutione boni quod amat, efficitur ei odiosus, non inquantum est similis, sed inquantum est proprii boni impeditivus.
But a man loves himself more than another, because he is one with himself substantially, whereas with another he is one only in the likeness of some form. Consequently, if this other's likeness to him arising from the participation of a form, hinders him from gaining the good that he loves, he becomes hateful to him, not for being like him, but for hindering him from gaining his own good.
Et propter hoc figuli corrixantur ad invicem, quia se invicem impediunt in proprio lucro, et inter superbos sunt iurgia, quia se invicem impediunt in propria excellentia, quam concupiscunt.
This is why "potters quarrel among themselves," because they hinder one another's gain, and why "there are contentions among the proud," because they hinder one another in attaining the position they covet.
Ille qui amat hoc quo indiget, habet similitudinem ad id quod amat sicut quod est potentia ad actum.
He that loves what he needs, bears a likeness to that which he loves, as what is in potency [bears a likeness] to its act.