Tafsiran Keluaran 2:20: Rashi, Chizkuni, Sforno & Or HaChaim

למה זה עזבתן — WHEREFORE HAVE YE LEFT [THE MAN]? — He recognised that he was of the offspring of Jacob because for him (Moses), as for Jacob, the water had risen in the well at his approach (Midrash Tanchuma, Shemot 11)

למה עזבתן, “Why did you abandon him?” According to Rashi, when Yitro heard that the waters from the well had risen at the approach of Moses, he realised that this man was someone special. The expression דלה דלה לנו, implies that the waters rose towards them as a result of Moses’ assistance.

למה זה עזבתן?, since he is a guest, and a person who has demonstrated kindness you should at least have reciprocated by showing him a measure of hospitality.

ויאכל לחם THAT HE MAY EAT BREAD — perhaps he will marry one of you — just as you say, (Genesis 39:6) “except the bread which he did eat” (cf. Rashi on this verse, where the word “bread” is explained as a euphemism) (Midrash Tanchuma, Shemot 11).