John Calvin Commentary Genesis 26:12

"And Isaac sowed in that land, and found in the same year a hundredfold. And Jehovah blessed him." — Genesis 26:12 (ASV)

Then Isaac sowed. Here Moses proceeds to relate in what manner Isaac reaped the manifest fruit of the blessing promised to him by God; for he says, that when he had sown, the increase was a hundredfold: which was an extraordinary fertility, even in that land. He also adds, that he was rich in cattle, and had a very great household.

Moreover, he ascribes the praise of all these things to the blessing of God, as it is also declared in the psalm that the Lord abundantly supplies what will satisfy his people while they sleep (Psalms 127:2). It may, however, be asked, how could Isaac sow when God had commanded him to be a stranger all his life?

Some suppose that he had bought a field, and so translate the word קנה (kanah) as 'a possession'; but the context corrects their error. For we find soon afterwards that the holy man was not delayed by having land to sell from removing his effects elsewhere. Besides, since the purchasing of land was contrary to his particular vocation and to the command of God, Moses undoubtedly would not have passed over such a notable offense.

To this may be added that since express mention is immediately made of a tent, we may therefore infer that wherever he might go, he would have to dwell in the precarious condition of a stranger. We must, therefore, maintain that he sowed in a hired field.

For although he had not a foot of land in his own possession, yet, so that he might discharge the duty of a good householder, it was his duty to prepare food for his family. Perhaps hunger also spurred his care and industry, so that he might make provision for himself with greater diligence for the future.

Nevertheless, it is right to keep in mind what I have recently alluded to: that he received as a divine favor the abundance which he had acquired by his own labor.