“The LORD bless him!” Naomi said to her daughter-in-law. “He has not stopped showing his kindness to the living and the dead.” She added, “That man is our close relative; he is one of our kinsman-redeemers.” Ruth 2:20
In days of the Old Testament, to keep a man’s property-land-inheritance in the family when he died, the law stated that a widow should marry a family member, preferably the next youngest brother.
If that were not the case, they would try to match her up with a cousin.
So the KINSMAN (a family member) REDEEMED (bought/protected/inherited) the widow and the family property.
In the case of Ruth, her husband and her brother in law died, so Boaz, an off-shoot of the family tree was next in line, a family member that protected Ruth and kept her legacy in the family.
God is called our redeemer.
I know that my Redeemer lives, and that in the end he will stand upon the earth. Job 19:25
May the words of my mouth and the meditation of my heart be pleasing in your sight, O LORD, my Rock and my Redeemer. Psalm 19:14
He saves us with his family name. He protects us to preserve his legacy in us.
In the same way, Jesus Christ redeems us—protects us, calls us to be a family member, buys us back by paying for the penalty of our sins. He calls us his brothers and sisters and wants to keep his inheritance, an eternal relationship with him, within the spiritual family.