Albert Barnes on Luke 12:15

Covetousness. An unlawful desire of the property of another; also a desire of gain or riches beyond what is necessary for our wants. It is a violation of the tenth commandment (Ex 20:17), and is expressly called idolatry (Col 3:5). Compare, also, Eph 5:3, Heb 13:5.

A man's life. The word life is sometimes taken in the sense of happiness or felicity, and some have supposed this to be the meaning here, and that Jesus meant to say that a man's comfort does not depend on affluence--that is, on more than is necessary for his daily wants; but this meaning does not suit the parable following, which is designed to show that property will not lengthen out a man's life, and therefore is not too ardently to be sought, and is of little value. The word life, therefore, is to be taken literally.

Consisteth not. Rather, dependeth not on his possessions. His possessions will not prolong it. The passage, then, means: Be not anxious about obtaining wealth, for, however much you may obtain, it will not prolong your life. That depends on the will of God, and it requires something besides wealth to make us ready to meet him. This sentiment he proceeds to illustrate by a beautiful parable.

(o) "Take heed" 1Timm 6:7-10 (p) "life consisteth" Job 2:4, Mt 6:25