I would like to offer my views on this subject.
First, it has been stated that "according to Baha'i scripture" only the following had the authority to declare a person as a Covenant-breaker: Baha'u'llah, the Master, the group of nine Hands of the Cause who worked most closely with the Guardian.
There is nowhere in the Baha'i Writings that says that Baha'u'llah has the authority to expel Covenant-breakers.
There is nowhere in the Baha'i Writings that says that Baha'u'llah has the specific authority to do *anything* in the Baha'i Faith. That is because as the Author of the Baha'i Faith, He had inherent authority to do anything He chose to do.
We know that He did expel people. Here, Baha'u'llah describes His expulsion of Siyyid Muhammad Isfahani, the Antichrist of the Baha'i Revelation:
"Subsequently, he committed that which -- I swear by God -- hath caused the Pen of the Most High to weep and His Tablet to groan. We, therefore, cast him out; whereupon, he joined Mirza Yahya, and did what no tyrant hath ever done. We abandoned him, and said unto him: "Begone, O heedless one!" After these words had been uttered, he joined the order of the Mawlavis . . . " (Baha'u'llah, Epistle to the Son of the Wolf, p. 164)
Further explanations of Baha'u'llah's words regarding Covenant-breakers are found quoted by the Master in His Last Tablet to America, found towards the back of "Baha'i World Faith."
There is no place in the Writings of Baha'u'llah stating that `Abdu'l-Baha had the specific authority to expel Covenant-breakers. There is nothing *within driving distance* of stating that `Abdu'l-Baha had the power to expel Covenant-breakers.
All that there is, is this statement:
"The Will of the divine Testator is this: It is incumbent upon the Aghsan, the Afnan and My Kindred to turn, one and all, their faces towards the Most Mighty Branch." (Kitab-i-`Ahd, Tablets of Baha'u'llah, p. 221)
This reiterates what Baha'u'llah had written to all the Baha'is in Paragraph 121 of the Aqdas.
The entire authority of `Abdu'l-Baha was contained in the single word, "turn". In the Tablet of the Branch, Baha'u'llah added that whoever turned toward `Abdu'l-Baha had turned toward God, and whoever had turned against `Abdu'l-Baha had turned away from Baha'u'llah. (The World Order of Baha'u'llah p. 135)
The entire authority of `Abdu'l-Baha, in the greatest Covenant ever written by a Manifestation to guide His followers, was placed in that single word, "turn" This is Covenant language. The authority of `Abdu'l-Baha to Himself write a Covenant, which He did in His Will and Testament, was contained in the word, "turn". `Abdu'l-Baha's powers were not, in any way, defined or limited.
The authority of `Abdu'l-Baha to expel Covenant-breakers *was not specified in the sacred Text*. It was inherent in the word "turn," which established the Master as the Head of the Cause.
This same word, "turn"; with the same promise of divine blessings on those who turn, and the same warning of divine punishment to those who turn away, is found in the Master's Will when He writes of the House of Justice and of the Guardianship (pp. 11 and 26).
The Hands of the Cause were authorized by the Master in His Will to expel Covenant-breakers. However, Shoghi Effendi as the Head of the Faith, withheld this power from the Hands during his lifetime, and only exercised it himself. He had the supreme power in the Cause, bestowed by the Master's Covenant. Under the Master's Will, the Hands of the Cause were directed by the Guardian of the Cause; so there was never any conflict in the authority in the Cause, and without hesitation they followed him.
Similarly, the House of Justice has this supreme authority in the Cause. Under the general power of the Covenant contained in the word "turn," the Hands of the Cause turned to and were directed by the Universal House of Justice. The ability to expel Covenant-breakers was ultimately the decision of the House itself; though the expulsion would be under the signature of the body of the Hands.
The House of Justice is not merely the supreme legislative body in the Faith. It is described by Shoghi Effendi as "the institution which must be regarded as the apex of the Bahá'í Administrative Order" (God Passes By, p. 332). It is promised infallible divine guidance flowing from both of the Manifestations, in the same sentence where this guidance is promised to the Guardian of the Cause (p. 11 of the Master's Will). The Universal House of Justice is given the same general authority as the Guardian was given, i.e. that everyone should turn to it, in the same sentence of the Master's Will as this authority was given to the Guardian of the Cause (p. 26).
The authority of `Abdu'l-Baha to expel Covenant-breakers rests not on a specific grant of authority to do so, but on Baha'u'llah's command that the Baha'is "turn" to `Abdu'l-Baha.
The authority of Shoghi Effendi to expel Covenant-breakers rests not on a specific grant of authority to do so, but on `Abdu'l-Baha's command that the Baha'is "turn" to the Guardian of the Cause and the Universal House of Justice.
The authority of the Universal House of Justice to expel Covenant-breakers rests not on a specific grant of authority to do so, but on `Abdu'l-Baha's command that the Baha'is "turn" to the Guardian of the Cause and the Universal House of Justice.