April 24th
Book Four, Chapter 18
That Man Should Not be a Curious Searcher Into This Sacrament, but a Humble Follower of Christ, Submitting His Sense to Holy Faith

You must beware of curious and useless scrutiny into this most profound Sacrament, if you would not sink into the depth of doubt....If you neither understand nor comprehend those things which are beneath you, how may you comprehend such as are above you?  Submit yourself to God, and humble your sense to faith, and the light of knowledge will be given you, according as shall be advantageous and necessary for you....Go forward, therefore, with a simple and undoubting faith, and with lowly reverence approach the Sacrament; and whatsoever you are not able to understand, securely commit to God the Omnipotent....If the works of God were such that they could easily be comprehended by human reason, they could neither be called wonderful nor unspeakable.