Albert Barnes Commentary Isaiah 7:21

"And it shall come to pass in that day, that a man shall keep alive a young cow, and two sheep;" — Isaiah 7:21 (ASV)

In that day – This refers to the time specified in the previous verses, namely, the period of judgments that would be brought upon the land by the Egyptians and Assyrians.

A man shall nourish – The Hebrew phrase means ‘to make live;’ that is, he will own or feed.

A young cow – The Hebrew term refers to a heifer that gives milk. This signifies a state of great poverty. Instead of engaging in agriculture or possessing great resources at that time, a man would depend for his and his family's subsistence on what a single cow and two sheep would yield. This is also likely intended as a description of the general state of the nation: it would be reduced to great poverty.

And two sheep – The number two here seems to denote a very small quantity. A man, that is, the average person, would be so impoverished as to be able to purchase and keep no more than this.