What is the key inference from the report of ʿazl “We used to do it while the Qur’an was being revealed”?

Isnād, Matn, Explicit and Constructive Marfūʿ, and Mawqūf

• The practice during revelation may indicate the absence of a prohibition
• All its routes must be equally authentic
• It is a verbatim command of the Prophet
• Companions never performed an incorrect act