Reason can appreciate the worth of worship, justice, cleanliness and beneficence. It cannot, solely from those general values, derive the number of prayer cycles, precise appointed worship times or all the detailed limits of permitted and prohibited actions.
Example: The benefits of cleanliness may be accessible to reason, but the prescribed limbs, conditions and sequence of ritual ablution are matters of revealed law.
A key benefit of messengership is therefore a dependable standard for practical decisions where broad rational guidance does not determine the exact rule.
The wisdom of revelation is not restricted to matters described as purely otherworldly. Human life, the benefits and harms of remedies, and complex practical decisions all display limits in available knowledge.
Medicine, observation and experience remain legitimate means of learning about worldly matters. Their finite reach, however, does not establish that any society possesses complete knowledge of every benefit and harm. Where revelation provides an authoritative instruction, that instruction has its own standing.
Empirical learning and prophetic guidance should each be understood within the appropriate domain rather than treated as unargued substitutes for each other.