Think about the hours people spend with thoughts that are not God's. Your thoughts will make you nervous, angry or pacify you as they minister outside of God's mind. Anything that is not God in thought is under the category of vain thoughts. But how do we not think our own thoughts if we have a mind to think with? Through Proverbs 16:3, we commit our works unto the Lord and our thoughts shall be established.
The only work we have left to commit is the work of believing (John 6:28). Committing faith becomes your only source of work. Our faith in His work establishes our mind in grace.
Our thoughts are like what our environment, our education and our religion has affected us with. But God eliminates our thoughts and speaks to us in His faith about our life. Do not become passive toward your thoughts, but revenge Satan's thoughts with obedience. If we do not do this, then we will not be in God's way. Thoughts produce ways. Many times people will not follow in the way of discipleship because they have their own thoughts. Jesus called people without definition. If He had given definition, they would have put it in their own thoughts and interpreted His call. Our thoughts always lead us to a way of temporal security. If Christ's thoughts had been that, He would never have gone to the Cross to end the old and start the new way through grace.