Matthew 6, Luke 6

As the Savior taught his followers and disciples many principles of righteousness, he counseled -

"Lay not up for yourselves treasures upon earth, where moth and rust doth corrupt, and where thieves break through and steal:
20 But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal:
21 For where your treasure is, there will your heart be also." (New Testament Matthew 6:19 - 21)

Suggesting -

"For as he thinketh in his heart, so is he..." (Old Testament Proverbs 23:7)

Our hearts is symbolizes our truest and most sincere desires. This becomes apparent as the Savior explains -

"The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.
23 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!" (New Testament Matthew 6:22 - 23)

Our hearts will either desire light or darkness. Neither can co-exist, therefore -

"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." (New Testament Matthew 6:24)

Elder Bruce R. McConkies wrote -

“Mammon is an Aramaic word for riches. Thus Jesus is saying, ‘Ye cannot serve God and riches, or worldliness, which always results from the love of money.’” (McConkie, DNTC, 1:240.)

The question for us all is are wordly riches and entertainment our treasure or is it faith in Jesus Christ. Nephi taught the same doctrine -

"...there shall be many which shall say: Eat, drink, and be merry, for tomorrow we die; and it shall be well with us.
8 And there shall also be many which shall say: Eat, drink, and be merry; nevertheless, fear God—he will justify in committing a little sin; yea, lie a little, take the advantage of one because of his words, dig a pit for thy neighbor; there is no harm in this; and do all these things, for tomorrow we die; and if it so be that we are guilty, God will beat us with a few stripes, and at last we shall be saved in the kingdom of God.
9 Yea, and there shall be many which shall teach after this manner, false and vain and foolish doctrines, and shall be puffed up in their hearts, and shall seek deep to hide their counsels from the Lord; and their works shall be in the dark." (Book of Mormon 2 Nephi 28:7 - 9)

"Because of pride, and because of false teachers, and false doctrine, their churches have become corrupted, and their churches are lifted up; because of pride they are puffed up.
13 They rob the poor because of their fine sanctuaries; they rob the poor because of their fine clothing; and they persecute the meek and the poor in heart, because in their pride they are puffed up.
14 They wear stiff necks and high heads; yea, and because of pride, and wickedness, and abominations, and whoredoms, they have all gone astray save it be a few, who are the humble followers of Christ; nevertheless, they are led, that in many instances they do err because they are taught by the precepts of men." (Book of Mormon 2 Nephi 28:12 - 14)

"O the wise, and the learned, and the rich, that are puffed up in the pride of their hearts, and all those who preach false doctrines, and all those who commit whoredoms, and pervert the right way of the Lord, wo, wo, wo be unto them, saith the Lord God Almighty, for they shall be thrust down to hell!" (Book of Mormon 2 Nephi 28:15)

Do we serve God or Mammon?