When ye be come into the land of Canaan, which I give to you for a possession. This is the first instance of a law being given which has no bearing on the present condition of the Israelites. but is to regulate their conduct when they had come into the promised land.
From the time of Abraham downwards, the assurance of their entrance into that land had been possessed by the people of Israel (Genesis 17:8), and the expectation of the speedy fulfillment of that promise had been quickened by their exodus from Egypt, and the preparations made to march through the wilderness.
There would, therefore, be nothing surprising to them in receiving instructions to guide their conduct when the entrance should have been effected. As the question is one of leprosy, it is natural that it should be treated of with the leprosy of the human subject and the leprosy of garments; but as it is not of immediate application, it is placed at the end, and dealt with after the rest of the subject has been discussed, being appended to the law of cleansing the leper, instead of preceding it.
And I put the plague of leprosy in a house of the land of your possession. This expression has led to the idea that the leprosy of houses was a special infliction at God's hand in a manner different flora other inflictions or diseases; but the words do not mean that.
All that is done is in a sense done by God, inasmuch as his providence rules over all; and, therefore, by whatever secondary cause a thing may be brought about, it is he that does it. It is God that feeds the birds (Luke 12:24), God that clothes the grass (Luke 12:28), nor does one sparrow fall to the ground without him (Matthew 10:29).
It is he, therefore, that puts the plague in a house, as the Lord of all things (cf. Isaiah 45:6, Isaiah 45:7, "I am the Lord, and there is none else. I form the light, and create darkness: I make peace, and create evil: I the Lord do all these things").
The expression militates, though not strongly, against the notion that the house caught the leprosy from the leper that lived in it.