John Wesley on Joshua 4:19

The first month - Namely, of Nisan, which wanted but five days of forty years from the time of their coming out of Egypt, which was on the fifteenth day of this month. So punctual is God in the performing of his word, whether promised or threatened. And this day was very seasonable for the taking up of the lambs which were to he used four days after, according to the law, Exod 12:3,6. Gilgal - A place afterwards so called, Jos 5:9.