Adam Clarke on Mark 6:11

And whosoever shall not receive you - Ὁς αν τοπος μη δεξηται, whatsoever Place will not receive you: this is the reading of BL, four others, and the later Syriac in the margin.

Verily, etc. - All this clause is omitted in BCDL, two others, one Arabic, one Persic, Coptic, Armenian, Vulgate, and all the Itala but three. Mill and Beza approve of the omission, and Griesbach leaves it out of the text. It has probably been transferred here from Mat 10:15. See this subject, from Mar 6:7-11, explained at large on Mat 10:1-15 (note).