A 33-year-old man is being dealt with in clinic after he was cut at the New Jerusalem Apostolic Church, in Aston, at around 10:50 BST.
He is in a steady condition and his wounds are not thought to be dangerous. A 46-year-old man is being hung on doubt of endeavored kill.
The other two individuals endured hand wounds as they endeavored to limit the knifeman, West Midlands Police said.
Early signs recommended the wrongdoer and casualty knew each other and it was a focused on assault, the power included.
In an announcement on Facebook, the congregation said three individuals from its assemblage were harmed.
None of the wounds were hazardous, it said.
The congregation stated: “As of now we are limiting doctor’s facility visits to family just and we will keep you refreshed as routinely as could be allowed.
“We might want to thank the greater part of our individuals and companions that were with us at the beginning of today for your participation, valiance and bolster and thank every other person for your petitions.”