Referring to a Messenger as a "Manifestation of God" is not shirk (Joining partners with God)
In the Baha'i sacred writings the term "Manifestation of God" is explained as follows;
The Manifestation of God is compared to a pure mirror. In the same way a mirror reflects the attributes of the sun such as heat and light, but the sun does not dwell to descend in the mirror, the attributes of God such as love, mercy, justice etc are reflected in the pure personage of the Manifestation of God, but God does not descend to dwell in the mirror of His holy Personage.
If we were to hear the radio say, "I'm Joe blogs on the morning show" we know the radio is not claiming to literally be Joe blogs, rather the radio does not assert it's independant existence, but rather relays the message as it is transmitted without mentioning itself.
Thus Baha'u'llah explains in the Kitabiqan,
..."Thus in moments in which these Essences of being1 were deeply immersed beneath the oceans of ancient and everlasting holiness, or when they soared to the loftiest summits of divine mysteries, they claimed their utterance to be the Voice of divinity, the Call of God Himself. Were the eye of discernment to be opened, it would recognize that in this very state, they have considered themselves utterly effaced and non-existent in the face of Him Who is the All-Pervading, the Incorruptible. Methinks, they have regarded themselves as utter nothingness, and deemed their mention in that Court an act of blasphemy. For the slightest whispering of self, within such a Court, is an evidence of self-assertion and independent existence"...
...'Thus, He hath revealed: “Those shafts were God’s, not Thine!”2 And also He saith: “In truth, they who plighted fealty unto thee, really plighted that fealty unto God.'...3
1 The Messengers of God
2 Quran 8:17
3 Quran 48:10
In the Baha'i sacred writings the term "Manifestation of God" is explained as follows;
The Manifestation of God is compared to a pure mirror. In the same way a mirror reflects the attributes of the sun such as heat and light, but the sun does not dwell to descend in the mirror, the attributes of God such as love, mercy, justice etc are reflected in the pure personage of the Manifestation of God, but God does not descend to dwell in the mirror of His holy Personage.
If we were to hear the radio say, "I'm Joe blogs on the morning show" we know the radio is not claiming to literally be Joe blogs, rather the radio does not assert it's independant existence, but rather relays the message as it is transmitted without mentioning itself.
Thus Baha'u'llah explains in the Kitabiqan,
..."Thus in moments in which these Essences of being1 were deeply immersed beneath the oceans of ancient and everlasting holiness, or when they soared to the loftiest summits of divine mysteries, they claimed their utterance to be the Voice of divinity, the Call of God Himself. Were the eye of discernment to be opened, it would recognize that in this very state, they have considered themselves utterly effaced and non-existent in the face of Him Who is the All-Pervading, the Incorruptible. Methinks, they have regarded themselves as utter nothingness, and deemed their mention in that Court an act of blasphemy. For the slightest whispering of self, within such a Court, is an evidence of self-assertion and independent existence"...
...'Thus, He hath revealed: “Those shafts were God’s, not Thine!”2 And also He saith: “In truth, they who plighted fealty unto thee, really plighted that fealty unto God.'...3
1 The Messengers of God
2 Quran 8:17
3 Quran 48:10