These are the remnant of the faithful, who have been mentioned already in Malachi 3:16, and who do not speak as many of their brethren spoke; that is, they did not share the idea that it was vain to serve God and that there was no profit in keeping his charge. They have lived in loving obedience to the Lord, trusting that in due time their faith, trust, and obedience would be rewarded. It is this reward that is alluded to in this verse.
2 But for you who fear my name, the sun of righteousness shall rise with healing in its wings. You shall go out leaping like calves from the stall.