Alas, you who are longing for the day of the LORD,
For what purpose will the day of the LORD be to you?
It will be darkness and not light;
As when a man flees from a lion
And a bear meets him,
Or goes home, leans his hand against the wall
And a snake bites him.
Will not the day of the LORD be darkness instead of light,
Even gloom with no brightness in it?
“I hate, I reject your festivals,
Nor do I delight in your solemn assemblies.
“Even though you offer up to Me burnt offerings and your grain offerings,
I will not accept them;
And I will not even look at the peace offerings of your fatlings.
“Take away from Me the noise of your songs;
I will not even listen to the sound of your harps.
“But let justice roll down like waters
And righteousness like an ever-flowing stream.
“Did you present Me with sacrifices and grain offerings in the wilderness for forty years, O house of Israel?
“You also carried along Sikkuth your king and Kiyyun, your images, the star of your gods which you made for yourselves.
“Therefore, I will make you go into exile beyond Damascus,” says the LORD, whose name is the God of hosts. (Amos 5:18-27)
The Day of the Lord was not a time of celebration. It was the time when God acted in judgment. Those who wanted justice might be among the first on the chopping block. Sure, while the Israelites wandered for forty years, they sacrificed to God. Sure, the Israelites continued to perform the required rituals as specified by the contract they made with God. Unfortunately, they also sacrificed to some other deities as well. So God would exile them in Babylon.
Sikkuth and Kiyyun were both false gods, most likely to be identified with Jupiter and Saturn. In Canaanite mythology, those two gods, Saturn and Jupiter were identified with El and Baal. They were part of Israel’s religious life even as far back as the wanderings in the wilderness. The worship of other gods is what motivated Joshua to famously stand before the people and ask them to “chose you this day” whom you will worship.
God had been very patient, gently working for a very long time in an attempt to turn his people from their tendency to mix the false worship with the worship of Yahweh. But sometimes, mercy had to end. Sometimes it became necessary to move on to something more harsh: the Day of the Lord.