Do not be astonished that I said to you, “You must be born from above.” The wind blows where it chooses, and you hear the sound of it, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit.’ Nicodemus said to him, ‘How can these things be?’ Jesus answered him, ‘Are you a teacher of Israel, and yet you do not understand these things?
‘Very truly, I tell you, we speak of what we know and testify to what we have seen; yet you do not receive our testimony. If I have told you about earthly things and you do not believe, how can you believe if I tell you about heavenly things? No one has ascended into heaven except the one who descended from heaven, the Son of Man. And just as Moses lifted up the serpent in the wilderness, so must the Son of Man be lifted up, that whoever believes in him may have eternal life.
(Lectionary, New Revised Standard Version)
A few weeks before a service was to be held by the Anglican Renewal Fellowship in Worcester cathedral the Dean asked me whether I would represent him and welcome the congregation and "top and tail" the service. I didn't think a lot about it, as a Minor Canon of the cathedral I was accustomed to doing this. The evening came and I should have guessed what would happen. The congregation sung choruses for a good three-quarters of an hour before the service actually started. It was glorious. The prayers and readings elicited "Yes brother!" and "Hallelujahs", and then it happened as individuals were being prayed over, they were falling to the floor. overcome by religious ecstasy. Being 'Slain in the Spirit' is a term used by Pentecostal and other Christians to describe being overcome God's Spirit.
Jesus says to Nicodemus that "he must be born from above". Unless the Holy Spirit gifts us with power we will never believe in Jesus. For many this came upon us at our baptism, at our confirmation, at our ordination, or at some other important event in our life. It is God's power that will turn Nicodemus from a timid follower of Christ into helping Joseph of Arimathea bury Jesus after his death (John 19.38-42). It is the power of the Holy Spirit that allows us to know that Jesus (as the 'Son of Man', ie the Messiah) after being lifted up on the cross, and rising again, has offered us eternal life.
As for those who were 'Slain in the Spirit', well God hasn't spoken to me in such a way, but I do believe He is the One who keeps me writing, and who answers my prayer - often unexpectedly and in ways I don't at first understand.
Holy Spirit,
speak to us this day.
Speak Your words of wisdom to guide us
in the direction we should take.
Speak Your words of comfort
to console or soothe us in our distress.
Speak Your words of power
to strengthen our faith;
Speak Your words of encouragement
to give us the patience we need to
continue growing as Your children.
Amen.
You might like to look at thes articles:
Or this video on the work of the Holy Spirit, produced by 'The Bible Project':