That outpouring of holy spirit was foretold in the words: “I [Jehovah] will pour out my spirit on every sort of flesh, and your sons and your daughters will prophesy...
وَكَانَ يَهْوَهُ قَدْ أَنْبَأَ بِذٰلِكَ حِينَ قَالَ :‏ « أَسْكُبُ رُوحِي عَلَى شَتَّى ٱلْبَشَرِ ،‏ فَيَتَنَبَّأُ بَنُوكُمْ وَبَنَاتُكُمْ .‏ .‏ .‏