Romans 11:18

μὴ κατακαυχῶ τῶν κλάδων : for the genitive see Buttm., 185. Between “if thou boastest,” and “thou bearest not the root,” there is no formal connection: for such breviloquence, which requires us to supply “consider” or “remember,” see Winer, p. 773. The sense is, You owe all you are proud of to an (artificially formed) relation to the race you would despise.