‘And Moses let his father-in-law depart, and he went his way into his own land.'
Having brought Moses his family, and having shared worship and hospitality with the children of Israel, Jethro returned home amicably, recognising that Moses now has in front of him his own destiny. The Egyptian plucked from the desert and given a welcome has become the ruler and guide of Yahweh's people.
It is probable that originally this was the end of a scroll or tablet. Exodus 19:1-2 bears all the marks of being an introduction to a new tablet, summarising the final part of this previous one.
Note for Christians.
The prime lesson from this passage is that of using wisdom in doing the work of God. We must be ready to learn wisdom from anyone, once we are satisfied that it really is wisdom. Moses might have bristled with pride against his father-in-law and pointed out that he was only the leader of a small wandering tribe, while he had this great mass of people to deal with. But the only loser would have been Moses. It is also an indication of the importance of putting in a word at the right time, and of doing it gently and tactfully.