Validation is one of the 4 activities in requirements development: Elicitation, Analysis, Specification and Validation.
Each requirement must be a valid requirement.
To determine if a requirement is valid, a Business Analyst, by inspection, will test it's alignment with the attributes of high-quality statements:
Complete, correct, feasible, necessary, prioritized, unambiguous and testable (verifiable)
And, with the attributes of high-quality specifications:
Consistent, modifiable, traceable
And, with the attributes of low-quality, unacceptable statements and specifications:
Incomplete, Untraceable, Inconsistent, Irrelevant, Incorrect, Ambiguous, Nonviable. Solution-Bound, Gold-plated, Creeping
If a requirement is not strongly aligned with the quality tests, the BA will facilitate the improvement of the alignment with it's owner and other stakeholders in one of the many requirements Walkthrough meetings during the development process.
Optionally, the BA can send out the requirements for review and feedback to stakeholders. But, the value of this "Desk Check" method is not a strong as simultaneous review by several individuals in a meeting.