53. They are the enemies of Christ and the pope who forbid altogether the preaching of the Word of God in some churches in order that indulgences may be preached in others.
It seems that Luther is here referring to the fact that some of the priests that were selling the indulgences were going away from their own parishes to travel to others to preach on indulgences. In this way they were denying the gospel to their own parish so that they could preach and sell indulgences at another church.
At that time all the physical needs of the priest would have been taken care of by the prince or duke or bishop that controlled the church community where they ministered. But those who sold indulgences would take a commission for each one that they sold. So this was a way for the priests to make money for themselves.
Sad to say that we still have ministers today that preach for their own gain. They have become experts at moving people to contribute to them. The people end up giving to the person who is preaching rather than making a gift to God in the worship.
Dear Lord, please protect me from those who seek to rob You. Let those who speak from the pulpit speak only Your word and not their own selfish desires. In Jesus Name. Amen.