John Calvin Commentary John 6:31

"Our fathers ate the manna in the wilderness; as it is written, He gave them bread out of heaven to eat." — John 6:31 (ASV)

Our fathers ate manna in the wilderness. Thus we see that Christ put His finger on the sore when He told them that they came like brute beasts to fill their belly, for they reveal this gross disposition when they demand a Messiah who would feed them.

Regarding the magnificent terms in which they extol the grace of God in the manna, they do this cunningly to bury the doctrine of Christ, by which He condemned them for an immoderate desire for corruptible food. For they contrast this doctrine with the magnificent title bestowed on the manna when it is called heavenly bread.

But when the Holy Spirit bestows on the manna the honorable title of the bread of heaven (Psalms 78:24), it is not with the intention that God fed His people like a herd of swine, giving them nothing more valuable. Therefore, they are without excuse when they wickedly reject the spiritual food of the soul, which God now offers them.