I Cor 7: 29- 32&35 “But this I say, brethren, the time is short, so that from now on even those who have wives should be as though they had none, 30 those who weep as though they did not weep, those who rejoice as though they did not rejoice, those who buy as though they did not possess, 31 and those who use this world as not misusing it. For the form of this world is passing away. 32 But I want you to be without care. 35 And this I say for your own profit, not that I may put a leash on you, but for what is proper, and that you may serve the Lord without distraction.”
So why do we have to stay away from materialism? Because the time is short for His coming. If we are powerless and weak how can we work for the kingdom of God and go into His fields for harvest? This is what Paul says in I Cor 7:29 – 32, here he speaks about marriage and how that should not be a hindrance to do the work of God, he also speaks about materialism which is another kind of cares of life. God wants to serve Him without the cares of this life. When we serve God then all will be added unto us. Seek the Kingdom of God first and all the rest will be added to us. Seeking the kingdom of God is serving God without the cares of this life. When we do this the things we buy or posses will not posses us, but we will posses them. Meaning we will not be a slave of these material things but they (Materials of this world) will serve us for the kingdom of God.