What is Islam?
Islam is the lifestyle that Allah (God) has chosen for mankind.
Monotheism
Islam has been built upon pure monotheism. Allah (God) is our creator, and he is the only one worthy of worship. Every act of worship must be exclusively done for Him
Worship only Allah and associate nothing with Him.
Acknowledge the creator
Allah (God) has made apparent His signs as a creator in everything around us.
In the creation of the heavens and the earth and the alternation of the night and the day are signs for those of understanding.
What is the purpose of life?
Our purpose in this life is to worship Allah. The concept of worship in Islam is very broad and includes anything done in obedience to Allah.
I did not create the jinn and mankind except to worship Me.
Allah sent us messengers
Since the beginning of time, Allah sent us messengers with His revelation, amongst them is Noah, Abraham, Moses, Jesus and Muhammad, all of them were sent with the same message: worship only Allah.
We have revealed to you, [O Muhammad], as We revealed to Noah and the prophets after him. And We revealed to Abraham, Ishmael, Isaac, Jacob, the tribes, Jesus, Job, Jonah, Aaron, and Solomon; and to David We gave the book [of Psalms]
The last message
Prophet Muhammad was the last and final messenger sent to mankind. Allah revealed the Quran to him for 23 years and inspired him with his Sunnah (his sayings and doings, which are an example for us to follow). In the Quran and the Sunnah of the prophet there is an explanation of the path we must follow until the end of times.
Just as We have sent among you a messenger from yourselves reciting to you Our verses and purifying you and teaching you the Book (the Quran) and wisdom (the Sunnah of the prophet) and teaching you that which you did not know.
The next life
After we die we will be resurrected and every human being will answer before Allah for his actions in this life. Those who accepted His messengers and worshipped only Him will enter paradise. Those who rejected His message will enter the fire. His judgement will be just and every action will be taken into account.
So whoever does an atom's weight of good will see it, and whoever does an atom's weight of evil will see it.