Joel 2:28-32 (Vespers, Saint John of Kronstadt)
Thus says the Lord: You shall know that I the Lord your God am in the midst of Israel, and there is none beside me, and my people shall no longer be ashamed for ever. And it shall be after these things that I will pour out of my Spirit upon all flesh, and your sons and your daughters will prophesy and your elders will dream dreams and your youths see visions. And upon my servants and my maid servants I shall pour out of my Spirit in those days, and they will prophesy; and I shall show wonders in the heaven above and signs in the earth beneath, blood and fire and the vapour of smoke; the sun will be transformed to darkness and the moon to blood, before the great and manifest day of the Lord comes; and it shall be that everyone who calls on the name of the Lord will be saved.