I'm no good with chapter and verse, but I remember a passage where Jesus advised people to, when they pray, go to their upper room and lock the door, and, when you give alms, not to let your left hand know what your right hand is doing. This isn't really relevant, I admit, but maybe there is a passage in the OT...
Maybe in Leviticus, or Deuteronomy? Possibly in one of the prophets...
Oh, right! There was part of an epistle where Paul condemned those who were "not keeping busy but acting like busy-bodies". If anyone knows the verse numbers, feel free to refresh my memory!
Maybe one of those will help...