What is the role of “not everything he says” after praise of a person’s diligence?

Supplementary Practice 7: Editing Expressions, Weighing Context and Rhetorical Critique

• Iḥtirās: blocking the inference of blanket endorsement
• Tadhyīl: placing a general maxim after a particular report
• Īghāl: additional meaning at a verse ending
• Omitting a necessary head noun