Allah's prophets are His messengers to humanity. Their essence is human, and they are the purest of human beings. Allah sent each prophet as a warner to his community until the advent of the final prophet, Muhammad (PBUH), who came as a mercy to all of Allah's creatures. Allah the Almighty declared: «And We have sent you (O, Muhammad) not but as a mercy for the 'Alamin (mankind, jinn and all that exists).» Surah 21: 107
Indeed, if it had not been for Muhammad (PBUH), we would not have known the true stories of the prophets as they took place. This is because their stories were distorted and corrupted before Muhammad's (PBUH) mission. The resulting versions did not respect the dignity and infallibility of the prophets. For example, the corrupt books of the Jews narrate a story of a prophet who drank alcohol and committed adultery with his own daughter; of a prophet who sent the commander of his army to war in order to ensnare the commander's wife; of a prophet who worshiped idols after marrying a pretty young idol-worshiper - they said he preferred to please her by worshiping her idol than to please his Creator. All the time you read these books you feel that you are confronting a false, confused, and misguided mentality which lies about Allah and His prophets.
If you leave the corrupt books of the Jews for those of the Christians, you will find a contrary attitude which is almost a reaction to the first. The Christians glorified their prophet Jesus (PBUH) to the degree that most of their sects call him the son of Allah. Allah is high above that!
The true image of the prophets was lost by either degrading or over-glorifying them. Were it not for the Qur'an we would not have known their true nature.
The prophets and messengers have different levels and degrees. Allah the Almighty stated: «Those messengers! We preferred some to others; to some of them Allah spoke (directly); others He raised to degrees (of honor).» Surah 2: 253
Despite the difference in degrees of prophets in the sight of Allah the Exalted, Muslims are commanded to respect them all and not to discriminate among them.
Allah the Exalted said: «Each one [of the believers] believes in Allah, His Angels, His Books, and His Messengers. They say, 'We make no distinction between one another of His Messengers" - and they say, "We hear and we obey." (We seek) Your forgiveness, our Lord, and to You is the return (of all)."» Surah 2: 285