The introduction to Paul's allegory on the olive tree in Rom 11 consists of two pithy halakic statements (v. 16) on the sanctification of mixtures and branches. Both refer to specific ancient Judean customs involving the dedication to God of agricultural real estate and farm products. In my opinion, neither has been properly identified. The first relates to the case of an unsacred liquid or foodstuff mixed in with a sacred offering; the second, to a byproduct self-generating out of a living dedication such as a plant or a tree. The two together fit Paul's larger message on the transference of sanctity to new members in communion with Israel. The statements can also enrich our understanding of the evocative olive tree allegory that follows.