Belief in all the messengers sent by Allah to mankind, without making distinction between them, is one of the pillars of the Muslim's creed without which his faith is invalid. Moreover, the denial of any messenger or prophet contradicts the basic principles of the religion. All prophets of Allah brought glad tidings of the advent of the last Prophet, Muhammd (may Allah's peace and blessings be upon him). Furthermore, many of the prophets and messengers sent by Allah to various nations were mentioned in the Noble Qur’an like Nūh (Noah), Abraham, Ismā‘īl (Ishmael), Is-hāq (Isaac), Ya‘qūb (Jacob), Yūsuf (Joseph), Moses, David, Sulaymān (Solomon), and Jesus, and there are others who were not mentioned. So, the probability that some of the religious characters in Hinduism and Buddhism, like Rama, Krishna, and Gautama Buddha, could be from the prophets who were sent by Allah is not totally far-fetched. However, there is no supporting evidence from the Noble Qur’an on that; thus, the Muslim must not believe in it. Differences between creeds appeared only when people started sanctifying and worshiping their prophets instead of Allah.
{We have sent messengers before you; of them are some whose stories We have told you, and some We have not. It was not for a messenger to bring a sign except with Allah’s permission. But when the decree of Allah comes, judgment will be passed with justice, thereupon the people of falsehood will be in utter loss.} [73] Surat Ghāfir: 78.
{The Messenger believes in what has been sent down to him from his Lord, as do the believers. All of them believe in Allah, His angels, His Books, and His messengers, [saying], “We make no distinction between any of His messengers.” And they say, “We hear and obey. Grant us Your forgiveness, our Lord, and to You is the [final] destination.”} [74] Surat al-Baqarah: 285.
{Say [O believers], “We believe in Allah and what has been sent down to us; and what was sent down to Abraham, Ishmael, Isaac, Jacob, and the descendants [of Jacob]; and what was given to Moses and Jesus; and what was given to the prophets from their Lord. We make no distinction between any of them, and to Him we have submitted.”} [75] Surat al-Baqarah: 136.