Deuteronomy 22:8 meaning

Moses then continued with the series of laws by which the Israelites were supposed to live. This law was concerned with someone wanting to build a new house (v. 8). Here, the requirement was that the builder needed to make a parapet for your roof. The term parapet (Heb. "ma'āqeh," used only here) refers to a protective barrier, and here it was to be placed around the edge of the roof to prevent people from falling off.

This parapet was much needed in ancient Israel because flat roofs were widely used, for instance, as a place for sleeping in warm seasons or as a place of recreation and relaxing (Joshua 2:6, 1 Samuel 9:25, 2 Samuel 11:2, 16:22, Isaiah 22:1, Jeremiah 19:13). So, the owner of a house would be putting the lives of his family members and visitors in great danger unless he built some sort of protective barrier. The idea is to invest in safety, to have regard for the welfare of others, to not put them in mortal danger.

This was important to do so that you will not bring bloodguilt on your house if anyone falls from it. In other words, a person building a house without a parapet would be guilty of willful negligence that could be a cause of death. Therefore, the Israelites were commanded to construct a parapet as a protective barrier in order not to be held accountable should someone step off the roof and fall. In short, the construction of the parapet would relieve the house's owner of the responsibility should a person fall from his roof.

The previous law (vv. 6 - 7) was designed to teach the LORD's covenant people that He cares for and values the lives of the least of His creatures. In this verse, He wanted to teach His people the importance of preserving and protecting human life, i.e. those made in His image. This all fits within the sixth commandment, that elevates the sanctity of life.