ואל-אצילי בני ישראל לא שלח ידו ויחזו את-האלקים ויאכלו וישתו
[Hashem] didn’t send His hand against the dignitaries of the Children of Israel, [although] they had seen G-d and ate and drank
After detailing various monetary and ritual laws, the Torah returns to the story of the Divine Revelation at Sinai. As the Jews were receiving the Torah, the dignitaries of the Jewish People feasted; they ate and drank. While this normally could have been justified, they were in front of the Divine Presence. The environment commanded a very high level of awe and respect. A public feast perhaps wasn’t appropriate at that moment, and the Torah seems to rebuke them for it. The Torah implies that the dignitaries could have been wiped out at that moment, but Hashem had compassion and spared them. One explanation is that this was to not ruin the celebratory event of the giving of the Torah. Instead, the dignitaries were later punished with death when they complained unjustifiably.