As he says in Hosea: "I will call them 'my people' who are not my people; and I will call her 'my loved one' who is not my loved one,"–Romans 9:25
It is written in the book of Hosea that Hosea's wife, Gomer, bore him a son. Afterward, it is written that Gomer bore two more children. These two children were evidently not Hosea's, so they were named, "Not Mine" and "Not Loved." Life for these children must have been difficult. Every time they were called on, they were reminded of their illegitimacy and the fact that they had no right to live in Hosea's house. Their only hope of a happy life and an inheritance was Hosea's grace. They could not obligate Hosea to show them any good. But, if Hosea wanted to do them good, he could: He could sovereignly call them "Mine", and sovereignly choose to love those who had no claim on his love.
What a beautiful picture of God's sovereign grace! By nature we are "Not Mine" and "Not Loved." Rather than children of God, we are children of wrath. We have no claim on God or His love. We have no home or inheritance. But in sovereign love and mercy, God has called us "Mine" and "Beloved."
I imagine that those children had a special love for Hosea as he took them as his own. And you can imagine how loved they felt when, in public, someone would call them by their old names, and Hosea would step forward and say, "No, let me introduce you to "Mine" and "Loved." And how blessed it is for us when law, conscience and Satan step up to call us by our old names only to hear God say through the gospel, "No, these are 'Mine,' and 'Loved.' In the very next verse Paul quotes, "It will happen that in the very place where it was said to them, 'You are not my people,' they will be called 'sons of the living God.'" Freewillers and legalists can have their "gospels". I rejoice in free and sovereign grace!
-JRT*