" . . . and the LORD shut him [Noah] in."
This account (above) is in reference to God's shutting the door of the ark, after Noah, his family, and all the animals had entered it. Noah did not shut the door, neither did those outside, who would be drowned. Instead, the Lord Himself did it.
God always "shuts" His people "in." The Lord secures His redeemed people in Jesus, and His church. No one can enter the doors He has finally closed; and no one can leave, once they are ushered in. So it is in the church today: all those who are regenerated by the Holy Spirit are "shut in," and they are glad to be so.
[Puritan quote of the day: "Touch a true godly man in his religion, and you touch his life and his best freedom; he lives more in his God than in himself . . . " --Richard Sibbes, in, "The Soul's Conflict with Itself"]