“Behold, I stand at the door, and knock: if any man hear My voice, and open the door, I will come in to him, and will sup with him, and he with Me” (Revelation 3:20). This is a prophecy in the Book of Revelation which predicts that the Lord Jesus will knock on the door when He returns, and every true believer in the Lord longs to welcome the Lord soon. But how will the Lord Jesus knock on the door when He comes? When the Lord Jesus knocks on the door, what should we do to welcome Him? This is something everyone who believes in the Lord should ponder deeply.