And Moses said to Hobab son of Reuel the Midianite, Moses’s father-in-law, “We are journeying to the place of which the LORD said to us, ‘It will I give to you.’ Come with us and we shall be good to you, for the LORD has spoken a good thing for Israel.” (Numbers 10:29, Robert Alter trans.)
R' Shlomo Kruger, a disciple of the Maggid of Dubno, was of the opinion that Moses was being disingenuous when making this offer to his father-in-law Hobab/Jethro:
Generally, when a person marries off a child and wants his friend to travel to him and take part in the wedding, he informs the friend of the wedding some time before, so that the friend will prepare himself in ample time. However, if he is not really sincere about his invitation and only invites the other out of courtesy, he only informs him at the last minute. That was what Moses did with Jethro.
Why?
Our Sages tell us that if a person wishes to become a Jew, one does everything possible to dissuade him, because we have had problems with converts. Thus Moses was not too anxious to have Jethro travel with the Israelites. On the other hand, it was not polite for him not to invite Jethro to come along. That is why he waited until the last minute before he invited Jethro.
This opinion of R. Shlomo Kruger is inconsistent with the rest of the pericope. After indicating his intention to return to his homeland and family, Moses pleads with his father-in-law: “Pray, do not leave us, for do you not know our encampment in the wilderness? And you will serve us as eyes. And so, if you go with us, by that good which the LORD will do for us, we shall be good to you.” (Numbers 10:31-32, Robert Alter trans.)
Biblical commentators are divided on whether Jethro continued on with the Israelites, but one thing is clear: when you have it in mind to include someone in what you are doing, the earlier you let them know about your plans, the better.
