Their Reward For Faithfulness And Obedience To His Covenant Will Be Multiplied Blessing (Deuteronomy 7:12-15).
a It shall come about that because you listen to these ordinances, and keep and do them, that Yahweh your God will keep with you the covenant and the lovingkindness (covenant love) which he swore to your fathers (Deuteronomy 7:12).
b And He will love you, and bless you, and multiply you, He will also bless the fruit of your body and the fruit of your ground, your grain and your new wine and your oil, the increase of your cattle and the young of your flock, in the land which He swore to your fathers to give you (Deuteronomy 7:13).
b You will be blessed above all peoples. There shall not be male or female barren among you or among your (your) cattle (Deuteronomy 7:14).
a And Yahweh will take away from you all sickness, and none of the evil diseases of Egypt, which you know, will He put on you, but will lay them on all them who hate you (Deuteronomy 7:15).
Note that in ‘a' Yahweh will keep covenant with them and show His covenant love towards them, and in the parallel He will therefore keep them from all the diseases of Egypt, and they will rather be put on their enemies. In ‘b' He will bless both their own production of children and the production of their beasts and crops and vines, and in the parallel there will be no barrenness either for them or their beasts.
‘ And it shall come about that because you (ye all) listen to these ordinances, and keep and do them, that Yahweh your (thy) God will keep with you (thee) the covenant and the lovingkindness which he swore to your (thy) fathers,'
And the result of their listening to His ordinances and keeping them in their hearts, and doing them, will be that He, Yahweh their God, will keep His covenant with them, and will maintain the covenant love (chesed), the warm, responsive, gracious love, which He swore to their fathers. With God relationship is always two way. Receiving mercy and love, must result in responding with love and obedience. The two go together. One cannot exist without the other. The person who does not seek to serve Him has not experienced His love and mercy, for His love and mercy would have changed their hearts so that they did love and obey Him.
‘ And he will love you, and bless you, and multiply you, he will also bless the fruit of your body and the fruit of your ground, your grain and your new wine and your oil, the increase of your cattle and the young of your flock, in the land which he swore to your fathers to give you.'
And He will not only keep covenant, but He will truly love them, and bless them, and multiply them. He first made the covenant because He wanted to pour out His love. But He will also bless both the fruit of their bodies, in healthy and numerous offspring, and the fruit of their ground in abundant harvests. Healthy offspring were necessary both in order to increase the number of hands available for work (compare Genesis 5:29) and in order to make the nation more powerful. He will also bless their crops and their fruit trees, their grain, and their new wine, and their olive oil. He will bless the young that their cattle produce, and the same with their flocks. They too will prosper and be fruitful and multiply and bring forth in abundance. And all this in the land which He swore to their fathers to give them, the chosen land, the land intended for the righteous, the land watched over by Yahweh, the potential kingdom of Yahweh.
‘ You (thou) shall be blessed above all peoples. There shall not be male or female barren among you (ye), or among your (your) cattle.'
Indeed they would be blessed more than all others. Not a single male or female would be barren, not one of their cattle would fail to produce in abundance. Their numbers and their prosperity would continue to grow and grow. All would be perfect. Here is the picture of abundant blessing, had they been fully faithful. But its final fulfilment would actually await the afterlife, for none in this world could live up to it.
‘ And Yahweh will take away from you (thee) all sickness, and none of the evil diseases of Egypt, which you know, will he put on you, but will lay them on all them who hate you.'
And they would suffer no sickness or disease. All the sickness that they had experienced and witnessed in Egypt would not trouble them. He will not put it on them, He will put it on those who hate them. ‘Which you know' - from bitter experience. One of the plagues involved painful boils which were prevalent in Egypt, along with afflictions of the eyes and bowels, to say nothing of more severe diseases. The fact that such diseases was for their enemies stresses that Yahweh also saw Egypt as their enemy and under judgment. For we may assume that the indication is that they had these diseases for that reason.
This deliverance from the ills of Egypt is stressed right from the beginning of their deliverance (Exodus 15:26; Exodus 23:25). It suggests that such ills were one of the downsides of life in Egypt.
All these descriptions point to the perfect state. This was their hope. Here was to be established heaven on earth. It was the picture which would again be presented eschatologically by the prophets, but here in Deuteronomy its fulfilment was theoretically to be expected fairly soon in the land. This in itself places Deuteronomy timewise before the prophets. It was a vision that could only be held while the prospect of possessing the land in this way in the near future was still expected.
But what is finally in mind is not the literal fulfilment, which could never happen because of man's sinfulness, but the final fulfilment when Christ submits all things to the Father and God is all in all (1 Corinthians 15:24-28). But they would not have understood that. Such thoughts would have been beyond them. It was therefore put in this way.