Haggai 2

“If one carries holy meat in the fold of his garment, and with the edge he touches bread or stew, wine or oil, or any food, will it become holy?”’” Then the priests answered and said, “No.” And Haggai said, “If one who is unclean because of a dead body touches any of these, will it be unclean?” So the priests answered and said, “It shall be unclean.” vv.12-13

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Why is it that one can transmit diseases but one can't transmit health?  Well that's a little bit of what's in question here between the priests and the Lord through Haggai.  If a meat is holy (set apart) if it touches other food it doesnt make that other food holy.  There is not a transmission of holiness.  Just like we can say of parents and children, if a parent is a believer, a holy or set apart person for Christ, their child isn't automatically a believer.  Yet if one is unclean according to the law because of touching a dead body and then touches any of the things listed (drinks and food) it will become unclean.  

Now people are influenced by the people around them, so one that lives a holy life can inspire others too as well, yet also one who lives in their sin can cause others to sin as well.  This passage reveals though that uncleanliness is transmitted much easier than holiness.  How have you seen that be true in or around your life?