Srimad Bhagavatham : 5.3. 16 & 17 :
Slokam-16 & 17.
Sri Suka Brahmarishi said: The priests, who were even worshiped by King Nabhi, the Emperor of Bharata-varsha, offered prayers in prose [generally they were in poetry] and bowed down at the Lord’s lotus feet. The Lord of lords, the ruler of the demigods, was very pleased with them, and He began to speak as follows.
The Supreme Personality of Godhead replied: O great sages, I am certainly very pleased with your prayers. You are all truthful. You have prayed for the benediction of a son like Me for King Nabhi, but this is very difficult to obtain. Since I am the Supreme Person without a second and since no one is equal to Me, another personality like Me is not possible to find. In any case, because you are all qualified brahmanas, your vibrations should not prove untrue. I consider the brāhmaṇas who are well qualified with brahminical qualities to be as good as My own mouth.
The word avitatha-girbhih means “they whose spoken vibrations cannot be nullified.” The brahmanas (dvija, the twice-born), are given a chance by the sastric regulations to become almost as powerful as the Supreme Lord. Whatever a brahmana speaks cannot be nullified or changed in any circumstance. According to the Vedic injunctions, a brahmana is the mouth of the Supreme Personality of Godhead; therefore in all rituals a brahmana is offered food (brahmana-bhojana) because when a brahmana eats, it is considered that the Supreme Lord Himself eats. Similarly, whatever a brahmana speaks cannot be changed. It must act. The learned sages who were priests at Maharaja Nabhi’s sacrifice were not only brahmanas but were so qualified that they were like devas, demigods, or God Himself. If this were not the case, how could they invite Lord Vishnu to come to the sacrificial arena? God is one, and God does not belong to this or that religion. In Kali-yuga, different religious sects consider their God to be different from the God of others, but that is not possible. God is one, and He is appreciated according to different angles of vision. In this verse the word kaivalyat means that God has no competitor. There is only one God. In the Svetasvatara Upanishad (6.8) it is said, na tat-samas cabhyadhikas ca drsyate: “No one is found to be equal to Him or greater than Him.” That is the definition of God.