As many as receive you not (οσο αν μη δεχωντα υμας). Indefinite relative plural with αν and present middle subjunctive and the negative μη. Here Matthew 10:14 has the singular (whosoever) and Mark 6:11 has "whatsoever place."

For a testimony against them (εις μαρτυριον επ' αυτους). Note use of επ' αυτους where Mark 6:11 has simply the dative αυτοις (disadvantage), really the same idea.