Satan is the god of this world, so if you are of this world then you place yourself under Satan. Jesus talked about the wealth we gain in Heaven, and how what we have on Earth is rust, turn to dust, etc, so material wealth to a Christian should be of a very low priority.
To get an idea of the importance you can look at the first 4 chapters or so of Acts, and see how the early church members gave up their material wealth, to help each other.
You can also look at how the one rich man walked away sad when Jesus told him to give up what he had and follow Jesus, as he couldn't separate himself from this world.
Adding some Scriptural references, but you may want to read the verses around these for more context.
John 12:31 (ESV)
31 Now is the judgment of this world; now will the ruler of this world be cast out.
2 Corinthians 4:4 (ESV)
4 In their case the god of this world has blinded the minds of the unbelievers, to keep them from seeing the light of the gospel of the glory of Christ, who is the image of God.
21 Then Jesus beholding him loved him, and said unto him, One thing thou lackest: go thy way, sell whatsoever thou hast, and give to the poor, and thou shalt have treasure in heaven: and come, take up the cross, and follow me.
22 And he was sad at that saying, and went away grieved: for he had great possessions.
Now the full number of those who believed were of one heart and soul, and no one said that any of the things that belonged to him was his own, but they had everything in common.
And they were selling their possessions and belongings and distributing the proceeds to all, as any had need.