Makhdum Zayn ud Deen Chishti quotes from Shaikh Suhrawardi’s (Allah have mercy on them) Awarif regarding inner conversation,

“excess inner conversation hardens the heart just as excess speech does, for it is like speech without a tongue…

A seeker must take account of his inward self, just as he does for his outward self. For inner speech, and remembering past affairs, which he saw or heard, is akin to speaking with another person inside himself.

So he should bind his inward self with awareness of the divine gaze and watch over it (muraqabah wa ri’aya), just as he binds his outward self with acts of obedience and various forms of invocation.”

The Guidance for the Intelligent