The expression bi-qadr al-ṭāqah al-bashariyyah defines the limit within which human beings interpret revelation. Language, context, other Qur'anic passages, the Sunnah and sound evidence help establish meaning; none permits a human interpreter to claim complete knowledge of every divine intention or wisdom.
This avoids two extremes: assuming no disciplined interpretation is possible, and treating every commentator's conclusion as absolute. Strong evidence should be followed, while genuinely probabilistic conclusions should be described with appropriate care.
Some aspects of ambiguous passages and unseen realities illustrate why a distinction must be maintained between what revelation makes known and what remains beyond our full comprehension.