Volume 3, Book 39, Number 514 :
Narrated by Abu Umama al-Bahili (radiallaahu `anhu)
I saw some agricultural equipment and said: “I heard the Prophet (sallallaahu `alayhi wasallam) saying: “There is no house in which these equipment enters except that Allah will cause humiliation to enter it.”
This statement, as the scholars have written, is to discourage or to show dislike. Reason being, people who would take that equipment home might get busy in farming and agriculture, and that might not leave them time or energy for jihaad (fighting for Allah’s cause). That time, as we know, was that of spreading of Islam, and a lot of battles were being fought. So Prophet (sallallaahu `alayhi wasallam) didn’t want the Muslims to be distracted by worldly stuff.
Also, those who’d take it up as a profession would be pursued by the government for taxes, and that’d lead to anything but respectful encounters, hence the statement: “Allah will cause humiliation to enter it (the house)”.