As Muslims, we are all obligated to believe and perform the 5 pillars. Not believing in the obligation of at least one of them, would take you out of the fold of Islam. It is also an obligation to perform them, although not performing them would not take you out of the fold of Islam, but would make you a sinner.
1. The Profession of Faith (Shahadah)
The profession of faith is a statement that every revert and every born Muslim, must recite at least once in their life. For a revert, this is the statement that brings you into the fold of Islam. Simply reciting this statement is not enough, but you must also believe it in your heart.
There are two components to the profession of faith:
1.1. I bear witness that there is no God but God
1.2 And I bear witness that Muhammad is the messenger of God
The first component is quite simple; to worship and believe in one God, and one God only. This is known as Tawhid.
The second component means that we must accept the prophet Muhammad, may peace and blessings be upon him, as a prophet and messenger of God, sent to mankind to spread Allah’s message.
2. Prayer (Salat)
Allah has told us in the Quran that He has only created us so that we should worship Him. Indeed, prayer is a very important aspect in Islam. We are instructed to pray 5 times a day at specific times. Prayer is an obligation upon us, meaning we will fall into sin if we do not perform our prayers.
3. Fasting (Sawm)
During the month of Ramadan, which may be 29 or 30 days, depending on the moon sighting, it is an obligation upon us to fast, by refraining from all food, drink, all forms of sexual pleasure, and intentionally vomiting. Muslims must start their fast at dusk, and must break their fast at sunset.
4. Charity (Zakat)
Every year, it is an obligation upon all Muslims who are financially capable, to give a portion of their savings to people in need. The exact amount is only 2.5% of your wealth. This 2.5% only applies to your assets and savings, and not to your income.
5. Pilgrimage (Hajj)
It is an obligation to perform the pilgrimage at least once in your life, if you are financially and physically able to. This pilgrimage is done by travelling to the holy city of Mecca, and performing specific religious rites.