20. what have I done to thee?—that is, Go, but keep in mind the solemn ceremony I have just performed on thee. It is not I, but God, who calls thee. Do not allow any earthly affection to detain you from obeying His call.

     21. took a yoke of oxen—Having hastily prepared (2Sa 24:22) a farewell entertainment to his family and friends, he left his native place and attached himself to Elijah as his minister.