Ten generations after Adam, people deviated from the truth, so Allah sent messengers. Ibn ‘Abbaas said:

“For the ten generations between Nooh [Noah ] and Adam people were adhering to the Deen. Thereafter, people deviated so Allah sent to them prophets, as givers of glad tidings (of Jannah) and as warners (of the Hellfire).” [ Haakim ]

The first messenger sent to humanity was Nuh a (Noah). Allah said:

“Verily, We have inspired you [O Muhammad s ] as We inspired Noah and the Prophets after him.” [ 4:163 ]

Allah has informed us in the Qur’an of the names of only a few Prophets and Messengers. Allah says:

(And that was Our [conclusive ] argument which We gave Abraham against his people. We raise by degrees whom We will. Indeed, your Lord is Wise and Knowing. And We gave to Abraham ,Isaac and Jacob - all[ of them ]We guided .And Noah ,We guided before; and among his descendants ,David and Solomon and Job and Joseph and Moses and Aaron .Thus do We reward the doers of good. And Zechariah and John and Jesus and Elias - and all were of the righteous. And Ishmael and Elisha and Jonah and Lot - and all[ of them ]We preferred over the worlds. And [some ] among their fathers and their descendants and their brothers - and We chose them and We guided them to a straight path.) [ 6:83-87 ]

Allah, the Exalted, would send messengers and prophets from time to time to guide people back to the Deen of Allah, and to worship Him.

Allah says:

(Say: [O believers], “We have believed in Allah and what has been revealed to us and what has been revealed to Abraham and Ishmael and Isaac and Jacob and the Descendants 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 we are Muslims [in submission ] to Him.”) [ 2:136 ]

Allah also says:

(And [mention ] Ishmael and Idrees(Enoch) and Dhul-Kifl; all were of the patient.) [ 21:85 ]

There are other Prophets and Messengers whom Allah did not inform us about. Allah says:

(And Messengers We have mentioned to you before, and Messengers We have not mentioned to you…) [ 4:164 ]

Allah, the Exalted, would send messengers and prophets from time to time to guide people back to His Deen, and to worship Him. All Prophets and Messengers conveyed the same Message, to worship Allah alone and to disbelieve in all things worshipped to the exclusion of Allah. Allah says:

(And We certainly sent into every nation a messenger, [saying], “Worship Allah and avoid false gods.” And among them were those whom Allah guided, and among them were those upon whom error was [deservedly ] decreed. So proceed through the earth and observe how was the end of the deniers.) [ 16:36 ]

The laws and legislations each nation was charged with differs; for some nations were charged with things other nations were not. The (wisdom) behind this is to test the obedience of those nations. Allah says:

(To each among you, We have prescribed a law and a clear way. If Allah willed, He would have made you one nation, but that He may test you in what He has given you; so strive as in a race in good deeds.) [ 5:48 ]

The last of messages, was the message of the Prophet Muhammad s who was sent to mankind at large. Allah says:

(Muhammad is not the father of any man among you, but he is the Messenger of Allah and the last of the Prophets.) [ 33:40 ]

One of the things that the Messengers of Allah called people to was that there is only One God worthy of being worshipped, Who disposes all affairs, and in whom they should seek refuge. This would lead them to spiritual happiness, and peace of heart and mind. Allah says:

(And We have only sent you [O Muhammad s ] as a mercy for all that exists.) [ 21:107 ]

The proof that those who believe in Allah and in the Message achieve true happiness is clear by contrasting their lives with the lives of those who deny the existence of Allah, reject the Shari’ah, and the confusion, anxiety and spiritual unrest they live through which causes them to take all forms of intoxicants to fill their spiritual void. It even drives some of them to commit suicide. These things would never lead one to happiness; even if one does feel happy, it is a short-lived happiness. It is like the one who drinks salty water; it would not quench his thirst, rather it would increase his thirst. Believing in Allah, far removed is He from every imperfection, submitting to Him, and obeying Him, would certainly efface all traces of sadness and make one achieve true happiness and comfort.