“Out of his mouth goeth a two-edged sword.”

"And further He saith: “Out of his mouth goeth a two-edged sword.” Know thou that since the sword is an instrument that divideth and cleaveth asunder, and since there proceedeth from the mouth of the Prophets and the Chosen Ones of God that which separateth the believer from the infidel and the lover from the beloved, this term hath been so employed, and apart from this dividing and separating no other meaning is intended. Thus, when He Who is the Primal Point and the eternal Sun desireth, by the leave of God, to gather together all creation, to raise them up from the graves of their own selves, and to divide them one from another, He shall pronounce but one verse from Him, and this verse will distinguish truth from error from this day unto the Day of Resurrection. What sword is sharper than this heavenly sword, what blade more trenchant than this incorruptible steel that severeth every tie and separateth thereby the believer from the infidel, father from son, brother from sister, and lover from beloved? 25 For whoso believeth in that which hath been revealed unto him is a true believer and whoso turneth away is an infidel, and such an irrevocable separation occurreth between them that they will cease to consort and associate with each other in this world. And so it is between father and son, for should the son believe and the father deny, they will be severed and forever dissociated from each other. Nay rather, thou witnesseth how the son slayeth the father and the father the son. Consider in the same light all that We have explained and related unto thee.

Wert thou to behold all things with the eye of discernment, thou wouldst indeed see that this divine sword doth cleave asunder generations. Would that ye could understand it! All this is by virtue of the word of separation that is manifested on the Day of Judgement and Separation, were the people to take heed in the days of their Lord. Nay, couldst thou but sharpen thy sight and refine thy heart, thou wouldst witness that all the material swords which in every day and age have slain the infidels and waged war against the impious proceed from this divine and invisible sword. Open then thine eyes, that thou mayest behold all that We have revealed to thee and attain unto that which none other hath attained. We verily exclaim: “Praise be to God, He Who is the Lord of the Day of Reckoning!” 26

Yea, inasmuch as these people have failed to acquire true knowledge from its source and wellspring, and from the ocean of fresh and soft-flowing waters that stream, by the leave of God, through hearts that are pure and stainless, they have been veiled from that which God hath intended by those words and allusions and have remained confined within the prison of their own selves."

-Bahá'u'lláh, Gems of Divine Mysteries (Javáhiru’l-Asrár), pp. 56-59

25. cf. Luke 12:53.
26. cf. Qur’án 1:4.