It is not necessary to lower Abraham to raise Jesus. It is not necessary to lower Jesus to proclaim Bahá'u'lláh. We must welcome the Truth of God wherever we behold it. The essence of the question is that all these great Messengers came to raise the Divine Standard of Perfections. All of them shine as orbs in the same heaven of the Divine Will. All of them give Light to the world.
The task is God's, and God calls not only the Prophets but all mankind to be His co-workers in this creative process. If we refuse His invitation, we shall not hinder the work from going on, for what God wills shall surely come to pass. If we fail to play our part He can raise up other instruments to perform His purpose; but we shall miss the real aim and object of our own lives. At-one-ment with God -- becoming His lovers, His servants, the willing channels and mediums of His Creative Power, so that we are conscious of no life within us but His Divine and abundant life -- that, according to the Bahá'í teaching, is the ineffable and glorious consummation of human existence.
~ Dr. J.E. Esslemont - Hand of the Cause of God In his introductory book entitled 'Baha'u'llah and the New Era' p. 255