Albert Barnes Commentary Deuteronomy 11:10

"For the land, whither thou goest in to possess it, is not as the land of Egypt, from whence ye came out, where thou sowedst thy seed, and wateredst it with thy foot, as a garden of herbs;" — Deuteronomy 11:10 (ASV)

Another motive for fidelity is added, namely, the entire dependence of the promised land upon God for its fertility. It was a land flowing with milk and honey; yet its richness was not, as was that of Egypt, the reward of human skill and labor, but was, on the contrary, the gift of God simply and entirely: the effect of the former and the latter rains sent by Him. The spiritual significance of these and many other such peculiarities of the promised land must not be overlooked.

Egypt and Canaan are distinguished in this and the following verses by certain of their most remarkable physical traits. Canaan, as a mountainous country , was well watered, but by the rains of heaven, on which it absolutely depended for its crops. Artificial irrigation could do nothing to remedy this dependence. Hence, it was a land on which, so long as God’s people were faithful and consequently prosperous, the eyes of God would always be; that is, He would supply at each successive season the useful conditions for productiveness.

But Egypt, a fitting emblem here as elsewhere of the world of nature in distinction from the world of grace, though of course deriving its all ultimately from the Giver of all good things, yet directly and immediately owed its riches and plenty to human ingenuity and capital. It enjoyed no rain worth speaking of, but drew its water supply from the annual overflowing of the Nile.

This only lasts about a hundred days; but is rendered available for agricultural purposes throughout the year by an elaborate and costly system of tanks, canals, forcing machines, etc. An allusion is made to these mechanical appliances (Deuteronomy 11:10). The inhabitants of Egypt probably watered with the foot in two ways: namely, by means of tread-wheels working sets of pumps, and by means of artificial channels connected with reservoirs, and opened, turned, or closed by the feet. Both methods are still in use in Egypt.