John Calvin Commentary Exodus 16:31

"And the house of Israel called the name thereof Manna: and it was like coriander seed, white; and the taste of it was like wafers [made] with honey." — Exodus 16:31 (ASV)

And the house of Israel called. It is not without reason that Moses repeats what he had said before: that the name Manna was given to the new kind of food which God had supplied. This was so that those who would dare to raise a question on such a manifest point might be brought under condemnation for their stubborn impiety, since the conspicuous nature of the thing had extorted this name from people otherwise malicious and ungrateful.

Its form is mentioned to prove the certainty of the miracle—namely, that its grains were round and like coriander seed—because nothing like it had been seen before. Its taste reproves the people’s ingratitude in rejecting a food that was not only appropriate and wholesome but also very sweet in flavor.