When we look at the opening of Peter's message to the Pentecost crowds, the prophecy from Joel 2, what's so particularly wondrous (apart from the fact that it's positively filled with wonders) is the relatively passive role that His people are meant to take in the unbridled active presence of the Holy Spirit. Just look at the way the verbs play out for God's sons and daughters:
‘And it shall come to pass in the last days, says God, that I will pour out my Spirit - meaning, Here He comes! Open up and simply receive what's being poured forth so liberally - on all flesh; your sons and your daughters shall prophesy - meaning, open their mouths to the direct words of God, not their own; they will be spoken through - your young men shall see visions - their natural field of vision will be overlaid with the supernatural; they will see God's sights - your old men shall dream dreams - they will lie down to rest and, through no effort of their own, be given God's dreams for the Church.
And on my menservants and on my maidservants I will pour out my Spirit - again, open up! be filled with this free offering - in those days and they shall prophesy - again, being spoken through. I will show wonders - sit back and watch! - in heaven above and signs in the earth beneath: blood and fire and vapour of smoke - whoa! The sun shall be turned into darkness - He'll do that - and the moon into blood, before the coming of the great and notable day of the Lord. And it shall come to pass that whoever calls on the name of the Lord - This is the prophecy's first available action of our own wills. This is the first time in Peter's words from Joel 2 that we are offered an independent action that requires our activity. Everything else is done to us, for us and through us - the Holy Spirit manifesting all the glorious power of Heaven - and all we're given to do is, by Belief, call upon the Name. Which nets us what? - [They] shall be saved.’ Be saved. Not save ourselves...
So in this present generation, these "last days" as Peter and Joel refer to our times, we are meant to be Holy-Spirit-poured-into, prophetic visionaries who dream His dreams, flooded by His Spirit and His words, and who are able to fearlessly observe the "signs of the times," call upon His name, and live out our salvations. Our active submission to His Way, to the Holy Spirit who now lives in us, creates a lifestyle that allows us to passively receive all the power and glory and purposes of the Kingdom for this world. What others might see as passive belief is actually our greatest action. From there, everything can springs from His plans, His power.