What is the purpose of prophecy? Why does it exist? If asked this question most would incorrectly respond with some variation of, “so we can know what’s going to happen in the future”. While foretelling future events can be prophetically spoken, knowing the future isn’t the point of purpose of prophecy. That’s divination.
Perhaps from others you might hear the more Biblically accurate, “to edify and encourage the church”. And while this second response is true it’s not the whole truth.
Yes one of the primary purposes of prophecy is to edify and encourage the church:
3 On the other hand, the one who prophesies speaks to people for their upbuilding and encouragement and consolation. – 1 Corinthians 14:3
Still others may say that prophecy serves as a sign, one for believers and they’d be right as well:
22 Thus tongues are a sign not for believers but for unbelievers, while prophecy is a sign[a] not for unbelievers but for believers. – 1 Corinthians 14:22
Yes, prophecy is most certainly for the exhortation and the upbuilding of God’s elect but that’s not its ultimate purpose.
The Glory of God is the ultimate purpose of all creation.
14 For the earth will be filled
with the knowledge of the glory of the Lord
as the waters cover the sea. – Habakkuk 2:14
36 For from him and through him and to him are all things. To him be glory forever. Amen. – Romans 11:36
“Holy, holy, holy is the Lord of hosts;
the whole earth is full of his glory!” – Isaiah 6:3
All things exist to glorify God; including his people, the Church. Additionally, the gifts he (the Holy Spirit) has given them all exist for the glory of God.
So it is with the gift of prophecy.
10 As each has received a gift, use it to serve one another, as good stewards of God’s varied grace: 11 whoever speaks, as one who speaks oracles of God; whoever serves, as one who serves by the strength that God supplies—in order that in everything God may be glorified through Jesus Christ. To him belong glory and dominion forever and ever. Amen. – 1 Peter 4:10-11
Edification, exhortation, tearing down, building up, forth telling and foretelling, preaching and teaching, can all be done prophetically, but none of those things in and of themselves is the purpose of God speaking.
No, the ultimate point and purpose of all those gifts, especially the gift of prophecy, is to glorify God.