It is incumbent upon all the friends of God to shun any person...

“Therefore, it is incumbent upon all the friends of God to shun any person in whom they perceive the emanation of hatred for the Glorious Beauty of Abhá, though he may quote all the Heavenly Utterances and cling to all the Books.” He continues—Glorious be His Name!—“Protect yourselves with utmost vigilance, lest you be entrapped in the snare of deception and fraud.” This is the advice of the Pen of Destiny.

- Abdul Baha

http://reference.bahai.org/en/t/c/BWF/bwf-128.html