Deuteronomy 7:9

7:9 So realize that the Lord your God is the true God, the faithful God who keeps covenant faithfully with those who love him and keep his commandments, to a thousand generations,

Deuteronomy 17:4

17:4 When it is reported to you and you hear about it, you must investigate carefully. If it is indeed true that such a disgraceful thing is being done in Israel,