The foundation of any religion is belief or faith. If you do not believe, it simply will not work. If you do not believe in God, you will not believe in any religion. You are said to be an Atheist. If you believe in some form of God, but not in religion, you are said to be a Deist.
Almost in all religions that I have read abut, the basis of belief is you " have to belief". My favourite is by the Jehovah Witness people who told me, you just have to belief, and you will be saved ! Wow, I thought, it's so easy ! And being told by an absolutely pretty unmarried lass, I am surprised at myself not being a JW member knocking at people doors telling them the end is near. But nope, at a teenager age, no one and nothing can take me away from my hobby.
Thus, in order to believe in religion, you have to belief in God. But in the history of mankind, there have been very many Gods. Animals have also been taken to be a God. When Muhammad came along, he needs to be and was very clear, that the God he is taking about is the God of the Universe, the God, or Allah in Arabic.
Therefore, you need also to believe that he, Muhammad, is the messenger of this God, else you would not believe in what he says, in his religion, in Islam.
So it is a very simple matter that if you want to believe in Islam, you need to believe in God and you need to believe that Muhammad is the Messenger of God. If you do not, for whatever reason, then you are not a Muslim. And therefore, we have the first and most important tenet of Islam, the Shahadah
In all religion, there is always some kind of ritual that gives the religion its identity, its character even. In Islam, the Prophet of Islam has prescribed prayers five times a day. If you have already accepted the first tenet of Islam, then you should follow this prayer ritual as recommended by the Prophet of Islam, because he says so and he defines Islam.
What about the millions of Muslim who do not pray ? Well, they are not following the Prophet of Islam, and therefore they are not following Islam. Period. What else do you want me to say ?
Prayers are prescribed in the Koran, but not five times a day. Prayers in the Koran is as and when needed, when your soul needs spiritual food. However this is difficult for the layman to translate, thus the Prophet of Islam puts form to something abstract, he commands a five times a day prayer.
I know very many millions of Muslims who do not pray will be very angry at me for saying this, but that is just the way it is in religion. That is how religion is constructed, and if you do not agree, go argue with the Prophet or Author of Islam. It is, if you like, the backbone of Islam, spine included.
There are a minority Muslims who follow only the Koran, and in that sense they are not Muhammadans. They pray to God and take all Prophets as Prophets ( Messengers ), not as Gods. We see them as liberal Muslims. They may be devout, but liberal. Mainstream Islam and Muslims reject this minority group as being "lost" and not following the Prophet.
In fact each Muslim group says the other is lost, and wanting to be absolutely correct in their rituals so that they can avoid Hell. The extreme fear of Hell, and believing all the Hell stories told to them made these Muslims a very particular very demanding and meticulous about their rituals. The Spirit of Islam is long forgotten, in favour of ritualistic Islam.
The zakat is charity in Islam. The sacrifice of 2½ % of your savings for the poor and needy is intended to save lives and help those in severe difficulties in life.
Now, if you profess to be a Muslim, and you have no compassion, no consideration, no emotions at all for the poor and the needy, you are perhaps worst than an Atheist who has love in his heart and helps the needy. That is my personal opinion of course, but zakat is compulsory in Islam, no exceptions. The poor in Islam are not exempted from zakat, they are given a portion of the zakat.
Thus in Islam, what the Zakat tenet is saying is that if you can help, please do. Allah wants you to help !
The Ramadan is the Arabic calendar month designated for Muslims to fast, by refraining from food and lust and exhibit excellent emotional control ( no bursts of anger, no wailing of despair ) during the day. It is, like solah or prayers, a discipline of Islam. It is prescribed by the Prophet of Islam.
The idea is for you to feel the suffering of those who have no money and no food and not much else. This will perhaps persuade you to have some kind consideration for the poor sufferings souls in the society. That is why among many other reasons imams and researchers can cook up, Muslims are required to fast. You will find on Muslim websites very many reasons why you should fast. Over here in the East, I fast too, and my reason is because everyone else does it, and I do not want to be left out. The other reason is that it is the law in some states here and you can be arrested and fined for eating in public, for not fasting. I do not want to be an outlaw, I don't want to break the law. But do I want to fast ? Noooh !
The pilgrimage to Mecca is called the Hajj. The idea is the congregation of people of the world from all walks of life devoted to worshipping the Allah, the God of the Universe. Indeed, today it is the largest single congregation of humans in the world, and perhaps that is testimony to the success of Islam as an ideology.
Another interesting fact is that the Kaaba in Mecca houses the stone which Abraham designated as symbolizing the house of God, and this is taken as the focal point for all the Abrahamic Religions, Judaism, Christianity and by Islam. It is an invitation to all other Abrahamic religions to accept Islam and come to one common ritual, but disallowing non-muslims access to Mecca does not help I think.
Whatever it is, it is not strictly imposed on Muslims, and the Prophet if Islam says that the pilgrimage is only to be done if one can afford it, financially and physically.
This is obviously focusing. Mecca is the focal point for Muslims World wide, and as the koran is meant for mankind, Mecca is then the focal point for mankind. This can be taken as the ambition of Islam. To conquer the World.