In the Genesis Noah's Ark story, God shut the ark's door after Noah, his family, and the animals entered. Genesis 7:16 describes the closing action at the start of the flood.
The verse first says that the creatures entered Noah as God had commanded, with the animals grouped according to their kinds. It then states that the Lord shut Noah in. This wording presents the closing of the ark as a divine action rather than a task Noah performed himself.
The detail is often simplified or omitted in children's retellings, which may show Noah closing the door. In the biblical text, however, Noah builds the ark, gathers the animals as commanded, and enters with his household, while God is the one who closes the entrance.
Genesis does not identify a separate doorkeeper, angel, or family member. The statement also emphasizes that Noah and those with him were enclosed before the waters rose, linking the door's closing directly to the beginning of the flood.