John Calvin on Luke 12:15

15. Take heed and beware of covetousness. Christ first guards his followers against covetousness, and next, in order to cure their minds entirely of this disease, he declares, that our life consisteth not in abundance. These words point out the inward fountain and source, from which flows the mad eagerness for gain. It is because the general belief is, that a man is happy in proportion as he possesses much, and that the happiness of life is produced by riches. Hence arise those immoderate desires, which, like a fiery furnace, send forth their flames, and yet cease not to burn within. If we were convinced that riches, and any kind of abundance, are evils of the present life, which the Lord bestows upon us with his own hand, and the use of which is accompanied by his blessing, this single consideration would have a powerful influence in restraining all wicked desires; and this is what believers have come to learn from their own experience. “Ce que les fideles experimentent ton les iours en eux-mesmes estre vray;” — “which believers every day experience in themselves to be true.” For whence comes it, that they moderate their wishes, and depend on God alone, but because they do not look upon their life as necessarily connected with abundance, or dependent upon it, but rely on the providence of God, who alone upholds us by his power, and supplies us with whatever is necessary?