Nehemiah 10:29-31

29these joined with their brethren, their nobles, and entered into a curse and an oath to walk in God’s Law, which was given by Moses the servant of God, and to observe and do all the commandments of the Lord our Lord, and His ordinances and His statutes:

30We would not give our daughters as wives to the peoples of the land, nor take their daughters for our sons;

31if the peoples of the land brought wares or any grain to sell on the Sabbath day, we would not buy it from them on the Sabbath, or on a holy day; and we would forego the seventh year’s produce and the exacting of every debt.