Caldecott, Stratford (Spring 2003). "Creation as a Call to Holiness". Communio. Archived from the original on 2013-04-14. Retrieved 2005-04-24. God creates whatever exists because it is fitting, not because it is necessary to him, nor because he is constrained by something outside himself. https://archive.today/20130414104327/http://conservation.catholic.org/caldecott_2.htm