Why “for yourself?” To teach that the first and best judge over human conduct is oneself.
Why “in all your gates”? To teach that the “gateways” in the body need to be especially guarded and watched.
According to the Sefer Yetzirah, the seven “gateways” are one’s two ears, two eyes, two nostrils and mouth.
None of these must be allowed to lead us astray – the ears by hearing what should not be heeded, the eyes by seeing what should not be observed, the nostrils by sensing what should not be noticed, and the mouth by saying what is best left unsaid.
A pertinent thought for Ellul, the month to prepare for the Divine scrutiny during the Days of Awe.