“The Day of the LORD (Yahweh)” seems to be prominent in the short book of Joel. Through Scripture it is used to indicate a time or times when God intervenes in humankind, often in judgement. In Joel “The Day” seems to include a couple of interventions.

The first refers to a locust plague, which would decimate the land. This could well have been a literal plague or it may have been a parable for the Babylonian invaders and the Exile. On balance though the former seems quite likely.

The plague and drought are followed by restoration and after that we have a passage which is quoted on the Day of Pentecost (Acts 2) by Peter, who associates it with the outpouring of the Holy Spirit on that day…

I will pour out my Spirit on all people.
Your sons and daughters will prophesy,
your old men will dream dreams,
your young men will see visions…
…I will pour out my Spirit in those days.

Pentecost, in its own way, was a “Day of the LORD”, but rather than a single event it was the beginning of ongoing outpouring (“in those days”). “Those days” are the age in which we now live and in Joel’s words they will then manifest in…

wonders in the heaven and on the earth,
blood and fire and billows of smoke.
The sun will be turned to darkness
and the moon to blood
before the great and dreadful day of the LORD.

Pentecost, with the outpouring of the Spirit, was a blessing, so this dreadful day would seem to refer to the future and final Judgement Day.

The good news is that in these days in which we live, following Christ’s death and Resurrection and the outpouring of the Spirit but prior to Christ’s Second Coming in Judgement, there is the opportunity to be ready for The Day…

And everyone who calls on the name of the LORD will be saved;
for on Mount Zion and in Jerusalem,
there will be deliverance…

Many Christians today have jettisoned any thought of hell or judgement from their theology in an attempt to make the Faith more palatable to their unbelieving contemporaries (I can be prone to this myself). They are happy to talk of love and mercy and grace, but punishment and righteousness and holiness and justice often drop out of their vocabulary. I am mindful of the fact that, in the Hebrew Scriptures, it was the false prophets who told people what they wanted to hear and painted a rosy future prior to the devastating Exile, which had been accurately predicted by God’s prophets – a small minority in Israel and Judah! We may not get many “Likes” for warning people about the coming Day of the Lord but it surely should be our passion to see our friends and neighbours safe on that day.