Matt
6:16-21
16“Moreover, when you fast, do not be like the hypocrites, with a sad countenance. For they disfigure their faces that they may appear to men to be fasting. Assuredly, I say to you, they have their reward. 17 But you, when you fast, anoint your head and wash your face, 18 so that you do not appear to men to be fasting, but to your Father who is in the secret place; and your Father who sees in secret will reward you openly.
19 “Do not lay up for yourselves treasures on earth, where moth and rust destroy and where thieves break in and steal; 20 but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal. 21 For where your treasure is, there your heart will be also.
Luther's Notes
Do not lay up for yourselves treasures on earth. Now, the Lord begins to warn against those temptations which hinder this doctrine, and takes up first the great beautiful vice of avarice. Also when Christ sent out his apostles to preach, his chief concern and warning was, that they should beware of two things — false doctrine and avarice. Matt. 10:9.We see that the whole world is immersed in avarice ; for every one is concerned day and night how he shall be nourished. And this promotes the avarice especially, that none are satisfied with what God has graciously bestowed upon them; all want more and to rise higher.
As for my person, who am called a Christian, I should not search anxiously for gold to be laid up, but cleave with my whole heart only to God. Yet outwardly, I shall make use of the temporal possessions, for my body and for the good of others, and gather gold and treasures, so far as my personality in the world is concerned; yet not too much of it, that I may not become a miser, who cares only for himself and can never be satisfied.
Where moth corrupt. With the words, Moth, etc., the Lord places three mine-workers along side of earthly treasures ; namely, rust, moth and thieves. Now God has wisely ordered, that where there are treasures, there must also be companions who watch over it. Now see what kind of a god Mammon is, who has no better watchmen and courtiers about him .
20 but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal.
Lay up for yourselves treasures in heaven. You, who are not of the world, but belong to heaven, and have been bought for this purpose by my blood, that you shall have an eternal inheritance, which has been prepared for you, do not let your hearts be taken in.
21 For where your treasure is, there your heart will be also.
Where your treasure is. If the heart is so disposed and shows it, where it can be shown that I would rather lose, not only gold and goods, but even my life, than forsake or despise the Gospel, and do injustice or violence to my neighbor for my own advantage, then I can conclude that gold and worldly goods is not the treasure of my heart.
Luther's Explanatory Notes on the Gospels, pp. 39-40.