'Grain' in the Bible

For it is written in the law of Moses, Do not muzzle an ox while it treads out grain. Is God really concerned with oxen?

Or has he us in mind? Yes, it was said for us; because it is right for the ploughman to do his ploughing in hope, and for him who is crushing the grain to do his work hoping for a part in the fruits of it.

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 that which thou sowest, thou sowest not that body that shall be, but bare grain, it may chance of wheat, or of some other grain: