Malachi 3:

16Then those who feared the Lord talked with each other, and the Lord listened and heard. A scroll of remembrance was written in his presence concerning those who feared the Lord and honored his name.

17“On the day when I act,” says the Lord Almighty, “they will be my treasured possession. I will spare them, just as a father has compassion and spares his son who serves him. 18And you will again see the distinction between the righteous and the wicked, between those who serve God and those who do not.

 Commentary
3:13-18 Among the Jews at this time, some plainly discovered themselves to be children of the wicked one. The yoke of Christ is easy. But those who work wickedness, tempt God by presumptuous sins. Judge of things as they will appear when the doom of these proud sinners comes to be executed. Those that feared the Lord, spake kindly, for preserving and promoting mutual love, when sin thus abounded. They spake one to another, in the language of those that fear the Lord, and think on his name.

As evil communications corrupt good minds and manners, so good communications confirm them. A book of remembrance was written before God. He will take care that his children perish not with those that believe not. They shall be vessels of mercy and honor, when the rest are made vessels of wrath and dishonor. The saints are God’s jewels; they are dear to him. He will preserve them as his jewels, when the earth is burned up like dross. Those who now own God for theirs, he will then own for his.

It is our duty to serve God with the disposition of children; and he will not have his children trained up in idleness; they must do him service from a principle of love. Even God’s children stand in need of sparing mercy. All are righteous or wicked, such as serve God, or such as serve him not: all are going to heaven or to hell. We are often deceived in our opinions concerning both the one and the other; but at the bar of Christ, every man’s character will be known.

As to ourselves, we have need to think among which we shall have our lot; and, as to others, we must judge nothing before the time. But in the end all the world will confess that those alone were wise and happy, who served the Lord and trusted in Him. Matthew Henry Commentary