“They shall be mine, says the Lord of hosts, in the day when I make up my treasured possession (Malachi 3:17a)

Malachi 3:16-18, ESV, Holy Bible
16 Then those who feared the Lord spoke with one another. The Lord paid attention and heard them, and a book of remembrance was written before him of those who feared the Lord and esteemed his name.
17 “They shall be mine, says the Lord of hosts, in the day when I make up my treasured possession, and I will spare them as a man spares his son who serves him.
18 Then once more you shall see the distinction between the righteous and the wicked, between one who serves God and one who does not serve him.