Or HaChaim on Leviticus 14:36/אור החיים על ויקרא י״ד:ל״ו

1 בטרם יבא הכהן, before the priest arrives. The reason the Torah had to write the word הכהן "the priest" again is, that otherwise I could have thought that the priest can issue directives before he arrives at the scene. According to that, the priest would not have had to delay himself until the people had cleared the house in question of all its contents. By writing the word הכהן, the Torah made it plain that the word בטרם is not linked to the mention of the priest as the one who issues the directive but is connected with the words ופנו "and they shall clear out."

2כל אשר בבית, everything that is within the house. The meaning is that none of the items that have been removed prior to the arrival of the priest will be affected by the declaration that the house and all its contents have become ritually impure. The reason is that G'd is concerned with the belongings of even the person for whom He expressed some disdain. We must ask ourselves that seeing this is so why did all these items have to be removed prior to the priest's arrival when the impurity decreed on these items does not become effective until after the priest's departure (compare verse 38)? The Torah wrote ולא יטמא כל אשר בבית, "in order that all that is in the house not become defiled," to teach us that once the priest has observed the symptoms on the walls of the house as being those of a נגע, he may not delay pronouncing the house and its contents as ritually unclean any longer. If the people in the house had waited until the last possible moment with removing all mobile objects they would most likely have forgotten some in their haste. It is better therefore that they should do so as soon as they became aware that the priest was on his way.

3We are taught in Keylim 12,5 that G'd's concern is only for earthenware vessels seeing all the other vessels are subject to purification rites except earthenware jars, etc. According to our explanation G'd is concerned even about very small and inexpensive earthenware vessels.