Its a expression/slang used by pentacostals and charismatics to
explain someone falling under the power of the Holy Spirit. The
person "slained" is said to fall backwards or downwards as the Holy
Spirit's annointing/unction falls on him/her. Some will break into
convulsion/jerking kind of bodily action while others may
experience crying, stillness or laughter as they claim that the
Holy Spirit touched them.
The bible did briefly mention this similar occurance in Daniel's
experience, Paul's conversion, Peter's vision and Jesus' capture.
After being in the pentacostal and charismatic circle for some
time, I realise that too much emphasis is placed on it. Some
pastors are not satisfied until they see you down on the floor.
Pastors pushing people down is the usual complain of negative
reports. While the positive reports come mostly from people who are
not touch when being prayed for.
Hope this helps
