Numbers Rabbah 8:2
The Holy One, blessed be God, greatly loves converts. To what may this be compared? To a king who had a flock which used to go out to the field and come in at evening. So it was each day. Once a stag came in with the flock. He associated with the goats and grazed with them. When the flock came in to the fold he came in with them; when they went out to graze he went out with them. The king was told: 'A certain stag has joined the flock and is grazing with them every day. He goes out with them and comes in with them.' The king felt an affection for him. When he went out into the field the king gave orders: 'Let him have good pasture, such as he likes; no man shall beat him; be careful with him!' When he came in with the flock also the king would tell them, 'Let him drink'; and he loved him very much. The servants said to him: 'Sovereign! You possess so many goats, lambs, and kids, and you never caution us about them; yet you give us instructions every day about this stag!' Said the king to them: 'The flock have no choice; whether they want or not, it is their nature to graze in the field all day and to come in at evening to sleep in the fold. The stags, however, sleep in the wilderness. It is not in their nature to come into places inhabited by man. Shall we then not account it as a merit to this one which has left behind the whole of the broad, vast wilderness, the abode of all the beasts, and has come to stay in the courtyard?' In like manner, ought we not to be grateful to the convert who has left behind him his family and his father's house, has left behind his people and all the other peoples of the world, and has chosen to come to us?
We live in an age in which we are all Jews by Choice. Whether born to Jewish parents or not, in 21st-century America our identities are a matter of our own selection. As such, we read this midrash as being about all of us who have "come to stay in the courtyard." Some of us, born to other traditions and religions, have indeed left behind other peoples and have had to negotiate with parents and extended family what it means to take on the religion and culture of the Jews. Others of us have grappled with what it means to have been born into this people, this flock, and have made decisions—are constantly making decisions—to live as members of the community. All of us should feel the warm praise of the midrash, full of gratitude and commendation, for the commitments we make and the ways we choose to live our lives as Jews.