I am sure almost everyone would agree that an open is a virtuous trait. What is an open minded person? It is person who is willing to honestly listen to different ideas. Religious people are often the most closed minded people that one will meet in their lives. They already have a set of beliefs and they do not want to hear any opposing views to them. It is fortunate that most religious people I come across in my life are open-minded people. If I have a disagreement with them they would listen to my point of view.
There is something even better than an open mind, and far fewer people actually have this, it is a free mind. A free minded person is a person who forms his beliefs without fear to the status quo or tradition or anything of that sort. He forms his beliefs in a way that makes the most sense without fear of challenging old existing ideas. A free minded person is necessarily open minded but open mindedness is not a sufficient condition to have a free mind.
Religious people can be open minded, I am even sure most of them are open minded, but they are not free minded. It is nearly impossible for a religious person to be free minded. Because in religion one has to accept certain statements that either may not make sense or go against what one already knows, a believer will have to make room for religious beliefs that he would not normally accept if he was not religious. Religion after all rests on faith. Faith is believing without knowing. Therefore, I say it is nearly impossible for a religious person to be free minded. I am sure there were free minded religious people. Galileo was probably one of them. He did after all challenge the Church and he even had his life endangered, but he will willing to take his observations to the most reasonable conclusion, in that sense he really was a free minded individual. But in modern times with all the knowledge we have about archeology and science it is nearly impossible to be a free minded religious person anymore because it would imply one has to be rebellious to some reasonable statements. Religion enslaves the human mind. To free one's mind one would first have to throw away the chains of religious slavery off his mind.