Acts 2:20 describes cosmic signs that Peter says will come before “the great and glorious day of the Lord.” In plain terms, the sun and moon will be disrupted in dramatic ways as a prelude to a decisive day when God acts openly in history. Peter spoke these words on the day of Pentecost in Jerusalem, quoting the prophet Joel to the crowd that had gathered after the Spirit came upon the disciples.
The sun will be turned into darkness, and the moon into blood, before the great and glorious day of the Lord comes.
Acts 2:20 (WEB)
What Acts 2:20 Means
The verse begins with “the sun will be turned into darkness,” a picture of light failing in the sky. In the Hebrew prophetic tradition, such imagery signals that the familiar order of things is being shaken. Darkness here is not random chaos but a sign that God is about to bring something to a head.
“The moon into blood” uses similar language of upheaval. Blood in prophetic writing often points to judgment or to the cost of a decisive event, so the verse pictures heaven itself marked by solemn, unsettling signs. Peter is describing the atmosphere surrounding a major turning point, not offering a calendar or a forecast.
The verse does not give a date, a timetable, or instructions for predicting the end. It says the signs come “before” the day of the Lord and presents that day as “great and glorious,” meaning both weighty and splendid. What it promises is that God’s purposes will reach their climax, and it leaves the timing in God’s hands.
The Context of Acts 2:20
Acts was written by Luke, the companion of Paul, as a second volume following his Gospel. He addresses his account to a man named Theophilus and writes for a largely Gentile readership who needed to understand how the message of Jesus spread from Jerusalem outward. Peter’s sermon in chapter 2 is among the first public proclamations of the risen Christ after Pentecost.
The verse sits inside a longer quotation from Joel 2, which Peter applies to what the crowd is witnessing. Just before it, he says the Spirit is being poured out on sons and daughters, young men and old men, and servants. Just after, he promises that whoever calls on the name of the Lord will be saved, and then turns to accuse his listeners of crucifying Jesus. Read in that setting, the signs in heaven frame a call to repentance and faith rather than a mere prediction about the sky.
Key Phrases in Acts 2:20
Joel 2:31
The sun will be turned into darkness, and the moon into blood, before the great and terrible day of the LORD comes.
(WEB)
This is the original prophetic text that Peter is quoting. Reading the same sign language in Joel’s own words shows how the early church understood its scriptures and why Peter could claim that Pentecost fulfilled ancient promises.
Acts 2:21
It will be that whoever will call on the name of the Lord will be saved.’
(WEB)
The verse that follows directly in Peter’s sermon offers the heart of the message. Once you have considered the dramatic signs, this promise of salvation for everyone who calls on the Lord brings the focus back to God’s welcoming invitation.
A Short Prayer From Acts 2:20
Lord, you hold the sun and the moon in your hands, and you are never surprised by the turning of the ages. When the world feels unsettled, steady my heart with the truth that your day is coming and that you are faithful to finish what you started. Give me eyes to see what matters most and courage to turn toward you while there is still time to call on your name. Keep me hopeful and awake, and let my life reflect the quiet confidence of someone who belongs to you. Amen.