Is it wrong for TV preachers to drive fancy cars or live in luxurious mansions?
This earth is evil and has been since the fall of mankind in the Garden of Eden. That is, the present world system is on a course directed by Satan, not by God. It is a rebellious place.
Jesus said that where a man's treasure is, there also is his heart (his deepest love and desires). Jesus said also that it is easier for a camel to go through the eye of a needle than for a rich man to see the kingdom of God. This is because, as Scripture says, the love of money is the root of all evil.
The apostles lived modest lives as they traveled with Jesus, and as they spread the Gospel after His death, burial and resurrection. The great Paul was a humble tent maker, and worked for a living so that he wouldn't take away from his witness for Christ.
Jesus is the supreme example. All creation could have been at His fingertips had he chosen to live that way on earth while in the flesh. Instead, He chose a humble lifestyle--in part, no doubt, so that His soul-saving message, not His lavish lifestyle, would get to the people He sought to reach.
Jesus said: "The foxes have holes, and the birds of the air [have] nests; but the Son of man hath not where to lay [his] head" (Matt. 8:20). God's Word says something about how one should and should not present himself as a Christian. "Abstain from all appearance of evil" (1 Thessalonians 5:22).
Satan offered Jesus the world and its riches, if the Lord would bow down and worship him. Jesus refused, because Satan and the world"s system of corrupted riches are thoroughly evil.
The Bible says further: "Therefore to him that knoweth to do good, and doeth [it] not, to him it is sin" (James 4: 7).
This is not to say that a minister should take a false or phony vow of poverty. He should provide for himself and his family. But, when a minister of the Gospel of Christ appears to live saturated with, and totally a part of, earthly riches, he sends out a message that says his heart is really on the wealth of this evil world system, not on the things of God.
As a minister sent from God, the preacher should know to do good in every respect. Therefore, if he does evil, or even appears to do evil, by selling out to the corrupted, rebellious world system, he is committing sin.