They shall never sell land, paddy, barley, sheep, goats, horses, calves, cows or buffalo. Rajadharma of Mahabharata explains, ‘To sell a goat is to sell Agni (fire). To sell a sheep is to sell Varuna (water) and Surya (sun). To sell food is to sell Prithvi (Earth or land).’ In this way by selling such things we sell away the presiding deities of the things mentioned.
Shatanand explains also that by selling away such things we may put ourselves into difficulties if poverty strikes and so be left with nothing to fend off. Also if one has excess grains then he should give away such grain to Sadhus, Brahmins, beggars and the poor. Thus they should never sell food grains, as that is the best duty.
Old grain may be exchanged for new as that is not considered as selling. Similarly the type of grain may be exchanged for another type (barter). In this way the Grihasta (householder) duty is upheld. Our Smruti explain, ‘In business, buying and selling are necessary but one should never act to profit selfishly.’