He “heard it from almost everyone [he] knew when [he] was a kid” in Jordan. You would say this “to someone who is lucky enough to show up just in time to share the food of the people he’s visiting.”
Original Script: حماتك بتحبّك
Transliteration: Hamatak but-hibbak
Translation: Your mother-in-law loves you
I did not understand the saying until I realized that the only way for it to make sense was if Arab mothers-in-law rarely like their children-in-law. I find this quite odd, since it goes against the general tendency of Arab families to be tight-knit. After that realization, I was able to connect the saying and its meaning. Generally, Arab families like to eat together, and tend to prepare more than enough food, so if someone is lucky enough to visit someone as they are eating, they are likely to have some with the family. The comparison is that the luck of someone that shows up coincidentally at mealtime is as lucky as one who is loved by their mother-in-law.