Adam Clarke on Deuteronomy 23:1

Shall not enter into the congregation, etc. - If by entering the congregation be meant the bearing a civil office among the people, such as magistrate, judge, etc., then the reason of the law is very plain; no man with any such personal defect as might render him contemptible in the sight of others should bear rule among the people, lest the contempt felt for his personal defects might be transferred to his important office, and thus his authority be disregarded. The general meaning of these words is, simply, that the persons here designated should not be so incorporated with the Jews as to partake of their civil privileges.