Full Idea
Prescriptivity is especially important if moral judgements are universalizable, for then we can employ golden rule-style reasoning ('do as you would be done by').
Gist of Idea
Universal moral judgements imply the Golden Rule ('do as you would be done by')
Source
Brad W. Hooker (Prescriptivism [1995], p.640)
Book Reference
'Cambridge Dictionary of Philosophy', ed/tr. Audi,Robert [CUP 1995], p.640