Here are a couple of quotes for your collection on Baha'u'llah;
"...For none knoweth the time of the Revelation except God. Whenever it appeareth, all must acknowledge the Point of Truth, and render thanks unto God." They that have turned aside from Me have spoken even as the followers of John (the Baptist) spoke. For they, too, protested against Him Who was the Spirit (Jesus) saying: "The dispensation of John hath not yet ended; wherefore hast thou come?" Now, too, they that have repudiated Us, though they have never known Us and have been at all times ignorant of the fundamentals of this Cause, knowing not from Whom it proceeded or what it signifieth, have spoken that which hath made all created things to sigh and lament. By My life! The mute can never confront the One Who incarnateth in Himself the kingdom of utterance. Fear God, O people, and peruse, then, that which hath been sent down with truth in the eighth Chapter of the sixth Vahid of the Bayan, and be not of such as have turned aside." Baha'u'llah : Epistle to the Son of the Wolf
"...In another connection He, likewise, saith: "Were He to appear this very moment, I would be the first to adore Him, and the first to bow down before Him." Be fair, O people! The purpose of the Most Exalted One (the Báb) was to insure that the proximity of the Revelation should not withhold men from the Divine and everlasting Law, even as the companions of John (the Baptist) were prevented from acknowledging Him Who is the Spirit (Jesus). Time and again He hath said: "Suffer not the Bayan and all that hath been revealed therein to withhold you from that Essence of Being and Lord of the visible and invisible." Should any one, considering this binding injunction, cling unto the Bayan, such a one hath, verily, passed out of the shadow of the blessed and exalted Tree. Be fair, O people, and be not of the heedless." Baha'u'llah : Epistle to the Son of the Wolf
"...These Magi said: "Where is He that is born King of the Jews? for we have seen His star in the east and are come to worship Him!" When they had searched, they found out that in Bethlehem, in the land of Judea, the Child had been born. This was the sign that was manifested in the visible heaven. As to the sign in the invisible heaven -- the heaven of divine knowledge and understanding -- it was Yahya, son of Zachariah, who gave unto the people the tidings of the Manifestation of Jesus. Even as He hath revealed: "God announceth Yahya to thee, who shall bear witness unto the Word from God, and a great one and chaste."By the term "Word" is meant Jesus, Whose coming Yahya foretold. Moreover, in the heavenly Scriptures it is written: John the Baptist was preaching in the wilderness of Judea, and saying, Repent ye: for the Kingdom of heaven is at hand." By John is meant Yahya." Baha'u'llah : The Kitab-i-Iqan
Abdul'Baha also mentions John the Baptist on many occasions (Elijah always comes first).
Regards Tony