H is the siglum for the “Holiness Code” a name for the group of laws within Lev 17-26 in which holiness is an important theme. H has traditionally been considered an earlier source that was incorporated in P, thus H can often be used synonymously with H, but also as something distinct from P. Debate is ongoing on whether H was ever a distinct unity before its incorporation or if was cobbled together of earlier materials by P. H and P do not always agree, and Milgrom has differentiated what he believes to be two distinct priestly theologies. H does not restrict holiness to only the temple and priests, as does P, but argues that all of the people and the land of Israel should be holy. This holiness is also not static, as in P, but dynamic since it can be gained and lost based on obedience. An important theory in the debate about H has been proposed by Israel Knohl in which he argues that H is not only later than P, but also extends outside of Lev 17-26 into other parts of the Pentateuch. The view is gaining more traction, though not all accept all of Knohl theory (such as the priority of the P source over D).
Coogan, Old Testament