Nehemiah 10:29-31

29hereby participate with their colleagues the town leaders and enter into a curse and an oath to adhere to the law of God which was given through Moses the servant of God, and to obey carefully all the commandments of the lord our Lord, along with his ordinances and his statutes.

30“We will not give our daughters in marriage to the neighboring peoples, and we will not take their daughters in marriage for our sons.

31We will not buy on the Sabbath or on a holy day from the neighboring peoples who bring their wares and all kinds of grain to sell on the Sabbath day. We will let the fields lie fallow every seventh year, and we will cancel every loan.