1. God will spare those who serve him (3:13-18)

Some cynical Israelites complained that serving God was futile. To them, the LORD Almighty allowed evildoers to prosper while those who carried out his requirements and went about like mourners received nothing. Their complaint was arrogance. The LORD promised compassion for those who feared and listened to him. They would be God's treasured possession (Ex 19:5). On the day of judgment all will see that God makes a distinction between the righteous and the wicked.

2. Fire for some, healing for others (4:1-6)

The day of the LORD will be a terrible day of fire for the wicked and not a branch will be left to them. However, for those who revere God, it will be a day of righteousness and joy. God will use the righteous as instruments of justice against the wicked (3). Until that day, we ought to remember God's law. Moreover, Elijah would come before the day of the LORD. This Elijah is John the Baptist who prepared the way for our Lord Jesus Christ (Mt 11:13,14)