John Stott says in his exposition of Acts 2: Pentecost has been called – and rightly – the first revival, using this word to denote one of those altogether unusual visitations of God, in which a whole community becomes vividly aware of His immediate, overpowering presence. It may be, therefore, that not only the physical phenomena (verse 2ff) but the deep conviction of sin (verse 37), the 3,000 conversions (verse 41) and the widespread sense of awe (verse 43) were signs of revival.

~ R. E. Davies, I Will Pour Out My Spirit