Sealed book of Mormon Ch.20

AND the Lord continued his commandments
cunto us, saying: Lay not up for yourselves
treasures on earth, where moth and rust doth
corrupt, and thieves break through and steal; but
lay up for yourselves treasures in heaven, where
neither moth nor rust doth corrupt, and where thieves do not break through nor steal.
For where your treasure is, there will your
heart be also. And the light of the body is the
eye; if, therefore, thine eye be single, thy whole
body shall be full of light. But if thine eye be
evil, thy whole body shall be full of darkness. If,
therefore, the light that is in thee be darkness,
how great is that darkness.
No man can serve two masters; for either he
will hate the one and love the other, or else he
will hold to the one and despise the other. Ye
cannot serve God and Mammon.
And when we received these
commandments from the Lord, we did not
understand the meaning of them. For we had
no desire for any of the treasures of the earth.
Yea, we did not know what we should even
consider as treasures of the earth. Therefore,
we could not lay up for ourselves those things
that we did not understand