mail doesn't apply rule

Hello

I set up a rule in mail Version 9.3 (3124) under 10.11.6 (15G17023) on a MacPro 4.1. Rule is to delete messages that contain an array of two specified words separated by a simple blank space. Mail doesn't apply this rule even though this array is present, legible in the mail and found in that message's raw source.

Any hint appreciated.