Again, the deliverance from Egypt was a signal demonstration of the sovereign grace of God. The Egyptians were judged with respect to their idolatry and the Israelites were rescued and spared in spite of having become associated with their oppressors in idolatrous practices. It is plain that the principle of sovereign grace alone will account for such facts. This is called “putting a difference between Israelites and Egyptians” (Exodus 8.23; 11.7). In harmony with this, it is repeatedly stated in the Pentateuch that the source of Israel’s privilege lies exclusively in free divine grace, not in any good qualities possessed by the people from themselves (Deuteronomy 7.7; 9.4-6). True, God’s love for the Mosaic Israel is traced back to His love for the fathers. This carries the relationship of free choice one step farther back but does not, in substance, alter its nature, for the fathers, too, were chosen in the sovereign love of God. The idea of sonship, here for the first time emerging (compare Genesis 6.2), belongs to the same train of thought (Exodus 4.22; Deuteronomy 32.6). Sonship is, from the nature of the case, unmeritorious. We also meet, again, the peculiar affectionate use of the verb “to know” previously met with in regard to Abraham (Exodus 2.24-25). Also, the verb “to choose” is used. This is peculiar to Deuteronomy (7.6-7; 14.2). Finally, the term “redemption” enters into religious use here. It’s specific meaning (different from such general terms as “to rescue,” “to deliver”) lies precisely in this, that it describes the loving re-acquisition of something formerly possessed. There is not yet, in the Old Testament, any reflection on that element, so easily associated with the conception, viz., that a redemption-price is paid. Only by way of metaphor this thought emerges in an isolated instance (Isaiah 43.3). The sense is, in the Pentateuchal passages, simply that of attachment shown in the renewal of the ancient ownership. Hence, in the later chapters of the prophecy of Isaiah, where the background is that of deliverance from exile, the term attains to great frequency. The passages in the Pentateuch are: Exodus 6.6; 15.13; Deuteronomy 7.8; 9.26; 13.5; 21.8.
From: Biblical Theology: Old and New Testaments by Geerhardus Vos (Grand Rapids: William B. Eerdmans Publishing Company, 1948), pp. 128-129.