From the whirlwind, Yahweh reveals His creative power to Job, challenging Job with a repeated “where were you when. . . ?”
The focus is on Yahweh’s power to create, but several times He describes His power as the power to set up dates and doors.
It was Yahweh who “enclosed the sea with doors” and “placed boundaries on it,” setting “a bolt and doors” (38:8, 10). The sear bursts from its “womb” wild and uncontrollable. Yahweh alone is Lord of the sea, and He shows that Lordship by setting boundaries.
If there are “doors” to the sea, then presumably they open and shut. They are mostly closed but sometimes open. Yahweh is the one who opens the doors of the sea, as He opens the windows of heaven, to unleash the waters. He is the one with the keys.
In 41:14, Yahweh describes His power over Leviathan. Only Yahweh can “open the doors of his face,” the doorway of his mouth, protected by sharp teeth.
Elsewhere in the Bible, the Lord’s command of doorway is linked to His residence in the closed temple and His power, in limited cases, to open doors (and windows) from heaven and into heaven. He opens the doors of heaven to release manna (Psalm 78:23); He opens windows to pour out blessings (Malachi).
Jesus with the keys must be Yahweh incarnate, dead, and risen, the true Janus, the God of the doorway, who opens and shuts, hence also the God of beginnings and endings and transitions.