In Genesis 15, Abraham is told to offer a sacrifice in which the sacrificial animals were divided in two. This was a time when God was going to give him a great promise concerning his posterity, and it was a numinous and holy moment.
But when birds came down upon the sacrifice, they were treating it as just so much carrion—and so Abram drove the birds away. They were unclean birds, and they had no business desecrating a clean sacrifice.
In the same way, as we approach this Table, which is a Table of sacrificial praise, lifted up on the thanksgiving of God’s people, do not let any unclean birds near your heart and mind. Come with forgiven hearts, and clean hands. Come with a song in your heart, and a song in your mouth.
Centrally, put away the vulture of envy and snark. If there is anyone in this room that you harbor malice toward, then when you look down at the bread in your hand, you should see unclean crows all over it. Imitate our father Abram, and scatter them.
How? Forgive one another. Love one another, Forebear with one another. Let it go. Whatever they did to you, it was a lot less than what you did to Jesus, and He let it go. So we have gathered to partake in love and joy, and to chase off the birds.
So come, and welcome, to Jesus Christ.