Congregation goes in one door and exits the opposite door. 

Ezekiel 46:9

“But when the people of the land come before the Lord on the appointed feast days, whoever enters by way of the north gate to worship shall go out by way of the south gate; and whoever enters by way of the south gate shall go out by way of the north gate. He shall not return by way of the gate through which he came, but shall go out through the opposite gate.” Ezekiel 46:9

Before we came to Jesus Christ for the forgiveness of sin, we entered through the door as sinners, and He accepted us as we were, “God demonstrates his own love for us in this: While we were still sinners, Christ died for us.” Romans 5:8 After being born again, we are not to return through the door of sin, but we begin walking through the door where Jesus Christ walks with us. “God is not unjust; He will not forget your work and the love you have shown Him as you have helped His people and continue to help them. We want each of you to show this same diligence to the very end, so that what you hope for may be fully realized. We do not want you to become lazy, but to imitate those who through faith and patience inherit what has been promised.” Hebrews 6:10-12

When we come into the presence of God by the remission of sin through Jesus Christ, we are never to go back. If we do, in my upbringing, that is called “backsliding” when a person turns around and leaves Christ to go back through the door of the old ways. The phrase, “stay on the straight and narrow” was encouragement used towards one another.