I took a look through the Old Testament to see where the word "redeemer" (go'el) occurs. It's used over 100 times in the Old Testament! Here's a quick summary of what I found:
In Genesis 48:16, Israel (Jacob) blesses two of his grandsons and refers to the Angel who has redeemed him from all evil.
Exodus 6:6 and 15:13 speak of when the LORD redeemed Israel from the land of Egypt.
Leviticus 25 and 27 give commands regarding the redemption of people, property, and sacrifices.
Number 5:8 gives commands regarding the redemption required when someone sins.
Numbers 35, Deuteronomy 19, and Joshua 20 discuss commands about establishing cities of refuge so a person can flee from the "avenger (redeemer) of blood" if a person accidentally killed someone. A murderer, on the other hand, may not be redeemed and must be executed.
In 2 Samuel 14:11 and 1 Kings 16:11, we see the term applied to a relatives (kinsmen) - the house of Baasha.
In Isaiah, the LORD calls himself the Redeemer of Israel many times, particularly in chapters 43-44, 48-49, 52, 54, and 63.
In Jeremiah 31:11 and 50:34, the LORD is called the Redeemer of Israel.
In Hosea 13:14, the LORD says that He will redeem Israel from death.
In Micah 4:10, the LORD says that He will redeem the daughter of Zion from her enemies.
In Psalms 19:14, 69:18, and 103:4, David speaks about how the LORD has redeemed him from his enemies and from destruction.
In Psalms 77:15 and 78:35, the writers speak of how God has redeemed Israel [from Egypt?].
In Psalm 72:14, the writer speaks of how the king's son redeems the poor and needy from deceit and violence.
Other Psalms speak of how God redeems His people from wrath, affliction, and enemies.
In Job 3:5 and Job 19:25, Job speaks of redemption and his Redeemer.
Proverbs 23:11 warns us that the fatherless have a mighty redeemer.
In Ruth, we see how Boaz redeemed the property of Elimelech and his sons from Naomi. He also redeemed Ruth, the widowed daughter-in-law of Elimelech and Naomi.
In Lamentations 3:58, the writer speaks of the LORD as the Redeemer of his soul.
Someday, I want to take a look at how the New Testament speaks of "the Redeemer" and "redemption." Who is redeemed? From what are they redeemed? By whom are they redeemed? I also want to take another look at Isaiah 63:3-4 to see if it relates to Revelation 19:13? As for now, though, it's time to save these notes and get some rest.