The letter to the Laodiceans clearly ends with an allusion to teh Song of Songs. Jesus knocks and seeks entry to the Bridal chamber of the church, where he will sup with His Bride, sup on His Bride (Revelation 3:20). As almost everyone notices, that reaches back to Song of Songs 5:1, the Bridegroom’s entry into the chamber, the mutual feast, and the knocking that immediately follows.
But the Song is already in view earlier in the message to Laodicea. What Jesus wants from that church is hot food or cold food, let us say spicy food and soothing drinks. What he does not want is food warmed over on a hot plate. He wants a love that burns with the flame of Yah, love strong as death. When He comes to feast on the Laodicean Bride, He finds the food distasteful, and spits it out. That makes sense of Revelation 3:16: Why is the church in the mouth of Jesus? Yes, Jesus is the land spewing out inhabitants; but Jesus is also the Bridegroom who cannot eat a bride who produces only bitter grapes and vinegar.