What does the Bible say about the Christian and riches? Is he allowed to possess wealth, or is he to forgo earthly treasure?
It depends upon his heart.
“Then He said to them, ‘Beware, and be on your guard against every form of greed; for not even when one has an abundance does his life consist of his possessions.’ And He told them a parable, saying, ‘The land of a rich man was very productive. And he began reasoning to himself, saying, “What shall I do, since I have no place to store my crops?” Then he said, “This is what I will do: I will tear down my barns and build larger ones, and there I will store all my grain and my goods. And I will say to my soul, ‘Soul, you have many goods laid up for many years to come; take your ease, eat, drink and be merry.’” But God said to him, “You fool! This very night your soul is required of you; and now who will own what you have prepared?” So is the man who stores up treasure for himself, and is not rich toward God.’” Luke 12:15-21.
The basic teaching in this parable is “what does it profit a man to gain the whole world, and forfeit his own soul?”, Mark 8:36. This man had provisions for many years, but hadn’t provided for his soul. And so he focused on the wrong part of life. But he doesn’t seem to be condemned for having goods, but rather it says, "So is the man who stores up treasure for himself, and is not rich toward God."
James speaks of the same, but even more forcefully,
“Come now, you rich, weep and howl for your miseries which are coming upon you. Your riches have rotted and your garments have become moth-eaten. Your gold and your silver have rusted; and their rust will be a witness against you and will consume your flesh like fire. It is in the last days that you have stored up your treasure! Behold, the pay of the laborers who mowed your fields, and which has been withheld by you, cries out against you; and the outcry of those who did the harvesting has reached the ears of the Lord of Sabaoth. You have lived luxuriously on the earth and led a life of wanton pleasure; you have fattened your hearts in a day of slaughter,” James 5:1-5.
Here, he is also speaking of the rich who do not know God; they have had a life of pleasure and unrighteous gain, but what will they do when the judgement comes?
But he also speaks of the rich Christian in a different place,
“But the brother of humble circumstances is to glory in his high position; and the rich man is to glory in his humiliation, because like flowering grass he will pass away. For the sun rises with a scorching wind and withers the grass; and its flower falls off and the beauty of its appearance is destroyed; so too the rich man in the midst of his pursuits will fade away,” James 1:9-11,
and again,
“Listen, my beloved brethren: did not God choose the poor of this world to be rich in faith and heirs of the kingdom which He promised to those who love Him?” James 2:5.
He doesn’t condemn the rich Christian for being rich; rather, he admonishes him to not set his heart upon his riches, for they will soon pass away, for they belong to this earth. For as the psalm says, “His spirit departs, he returns to his earth; In that very day his plans perish.,” Psalm 146:4.
And so Paul says,
“Instruct those who are rich in this present world not to be conceited or to fix their hope on the uncertainty of riches, but on God, who richly supplies us with all things to enjoy. Instruct them to do good, to be rich in good works, to be generous and ready to share, storing up for themselves the treasure of a good foundation for the future, so that they may take hold of that which is life indeed,” 1 Timothy 6:17-19.
Unlike the man in the parable in Luke, who stored up his earthly riches, but was not rich towards God, the rich Christian is admonished not to put his trust in the “uncertainty of riches,” but rather to store up godly treasure. For if we put our hope in the “uncertainty of riches,” who knows what will occur? We may lose our fortunes in a bad venture, or the winds of politics might shift, and what once was safe may become perilous. But if we put our hope in Him, then rich or poor, we shall never be in want of the things that are needful,
“Do not worry then, saying, 'What will we eat?' or 'What will we drink?' or 'What will we wear for clothing?' For the Gentiles eagerly seek all these things; for your heavenly Father knows that you need all these things. But seek first His kingdom and His righteousness, and all these things will be added to you,” Matthew 6:31-33.
So it isn’t whether we have riches, or a humble existence, it is our attitude towards earthly treasure that is key.
Now, the pursuit of earthly wealth is a potential trap for the Christian,
“But those who want to get rich fall into temptation and a snare and many foolish and harmful desires which plunge men into ruin and destruction. For the love of money is a root of all sorts of evil, and some by longing for it have wandered away from the faith and pierced themselves with many griefs,” 1 Timothy 6:9-10.
If we turn to pursue earthly wealth, we have taken our eyes off of Christ, and put them on that which will pass away. As Christians, our focus is not to be on the things of this earth, but on heavenly things,
“Do not store up for yourselves treasures on earth, where moth and rust destroy, and where thieves break in and steal. "But store up for yourselves treasures in heaven, where neither moth nor rust destroys, and where thieves do not break in or steal; for where your treasure is, there your heart will be also,” Matthew 6:19-21.