Catechism of the Catholic Church

Wikipedia on Catechism

Catechism on the Vatican’s Website Table of Contents

2410 Promises must be kept and contracts strictly observed to the extent that the commitments made in them are morally just. A significant part of economic and social life depends on the honoring of contracts between physical or moral persons – commercial contracts of purchase or sale, rental or labor contracts. All contracts must be agreed to and executed in good faith.