The comprehensive theme of redemption is dealt with in 150 texts of Scripture, where a dozen Hebrew and Greek words are used. The term means to deliver by paying a price, to sever from bondage.
In OT days a lost inheritance could be redeemed, Lev. 25:25, as could an Israelite who had sold himself into bondage, Lev. 25:47, 48. The plan called for a kinsman redeemer, a near relative who was willing, Lev. 25:48, 49; Ruth 3:12, 13 and able to redeem, Lev. 25:26; Ruth 4:3-6.
A series of 18 passages in the OT present God as Redeemer, Psa. 19:14; Isa. 41:14; 48:17. The most famous of these texts is Job 19:25, “I know that my redeemer liveth.” Such passages speak of Christ our Brother, Isa. 8:18; Gal. 4:4, 5; Heb. 2:9-15. He was able and willing to redeem lost humanity, Heb. 10:4-10, “sold under sin,” Rom. 7:14. He paid the price of His own blood, John 10:11, 18; Acts 20:28; 1 Pet. 1:18, 19.
Three important words are used of redemption in the Greek: (a) to buy in the market, 1 Cor. 6:20; Rev. 5:9; (b) to buy out of the market so that the person or thing cannot again be sold, Gal. 3:13; 4:5; (c) to set free, Tit. 2:14; 1 Pet. 1:18. A time of restitution of all things is coming, Matt. 19:28; Acts 3:21, when believers will experience the redemption of their bodies, Rom. 8:18-23.
William Evans, The Great Doctrines of the Bible, (Chicago: Bible Institute Colportage Assoc., 1912), WORDsearch CROSS e-book, Under: “Redemption”.