Besides, consider what in our blindness, we have hitherto been
practicing and doing under the Papacy. If any one had toothache, he
fasted and honored St. Apollonia [lacerated his flesh by voluntary
fasting to the honor of St. Apollonia]; if he was afraid of fire, he
chose St. Lawrence as his helper in need; if he dreaded pestilence, he
made a vow to St. Sebastian or Rochio, and a countless number of such
abominations, where every one selected his own saint, worshiped him,
and called for help to him in distress. Here belong those also, as,
e.g., sorcerers and magicians, whose idolatry is most gross, and who
make a covenant with the devil, in order that he may give them plenty
of money or help them in love-affairs, preserve their cattle, restore
to them lost possessions, etc. For all these place their heart and
trust elsewhere than in the true God, look for nothing good to Him nor
seek it from Him.

Thus you can easily understand what and how much this commandment
requires, namely, that man's entire heart and all his confidence be
placed in God alone, and in no one else. For to have God, you can
easily perceive, is not to lay hold of Him with our hands or to put Him
in a bag [as money], or to lock Him in a chest [as silver vessels]. But
to apprehend Him means when the heart lays hold of Him and clings to
Him. But to cling to Him with the heart is nothing else than to trust
in Him entirely. For this reason He wishes to turn us away from
everything else that exists outside of Him, and to draw us to Himself,
namely, because He is the only eternal good. As though He would say:
Whatever you have heretofore sought of the saints, or for whatever
[things] you have trusted in Mammon or anything else, expect it all of
Me, and regard Me as the one who will help you and pour out upon you
richly all good things.