כִּֽי־תֵ֭שֵׁב לִלְח֣וֹם אֶת־מוֹשֵׁ֑ל בִּ֥ין תָּ֝בִ֗ין אֶת־אֲשֶׁ֥ר לְפָנֶֽיךָ׃
When thou sittest to eat with a ruler, consider well him that is before thee;
Rashi on Proverbs
you should understand well Give thought to know who he is, whether he is stingy or generous.