2 Samuel 15:11 - Ellicott's Commentary On The Whole Bible

Went in their simplicity. — The two hundred guests whom Absalom had invited to take part with him in his sacrifices, were doubtless prominent and influential citizens of Jerusalem. That they were entirely ignorant of Absalom’s purposes shows the extreme secrecy with which the affair was managed. Absalom, no doubt, hoped when he once had them at Hebron, to secure them for his side, or, failing this, forcibly to prevent their opposition. In any case it would appear to the people that they were with him, and he would thus secure additional prestige.