‘ And you shall consider in your heart, that, as a man chastens his son, so Yahweh your God chastens you.'
Furthermore when they are tested, as they were then and will be, they must consider in their hearts that just as a man chastens his children for their good, so does Yahweh chasten them, His children. Here again He emphasises that He is to them as a father. Remembering the lesson of God's provision of the manna when all seemed hopeless, and the chastening that a good father always gives to his children, they should then be enabled to walk into the future with confidence, even in the face of adversities.
This is the second clear indication in Deuteronomy that they are His sons and daughters. Previously He had been pictured as like a father carrying His son on His shoulders through the wilderness (Deuteronomy 1:31). Now He is like a father chastening them for their good. In all this His fatherly care is revealed to His son, His firstborn (Exodus 4:22). He was depicting Himself as their Father (compare Deuteronomy 14:1 where he says ‘you are the sons of Yahweh your God').