'Grain' in the Bible

For in the Law of Moses it is written, "Thou shalt not muzzle an ox while it is treading out the grain."

If it is we who sowed the spiritual grain in you, is it a great thing that we should reap a temporal harvest from you?

and as for what you sow, it is not the plant which is to be that you are sowing, but a bare grain, of wheat (it may be)