'Maintain' in the Bible

"{And then} because you listen [to] these regulations and you diligently keep and you do them, then Yahweh your God will maintain his covenant and his loyal love that he swore to your ancestors.

then his sister-in-law must approach him in view of the elders, remove his sandal from his foot, and spit in his face. She will then respond, "Thus may it be done to any man who does not maintain his brother's family line!"