To believe that there is no God but God and that Muhammad (peace be upon him) is His last and final Messenger.
I bear witness that there is no deity worthy of worship except the One God, and I bear witness that Muhammad (peace be upon him) is the Servant and final Messenger of God.
Ash-hadu anla ilaha illal-Lahu Wahdahu la Sharika Lahu wa-ash-hadu anna Muhammadan abduhu wa rasuluhu.
The fundamental belief of Islam is the Unity of God. To believe that there is only One God. That God has no associates, partners, accomplices, or other “divine nature” that works alongside Him. The declaration of faith dictates that God is One and Only, Unique, Absolute, above and exalted over His creation. He is One; He is Unique; He neither begets, nor is begotten. He is Almighty and Self-Sustaining. He is not in need of time or space. Neither sleep overtakes Him nor slumber. He is the Creator and we are the creation. This means we are limited in every way and He is unlimited. We are finite, and He is infinite. Our existence is temporary according to His decree, and His Divine Existence is everlasting and everexisting. These factors alone make Him unlike any other. Since God entails all of these qualities, that man can not he is God-Like. Therefore it is only fair that He is the only who should deserve to be recognized as God.
The Holy Prophet is the last prophet who brought us the last Book (the Holy Quran) to be followed. He lived among his people for a long time and his life is documented in utmost detail. He led his followers by example. The way he lived his life and admonished his followers to live their lives is called Sunnah of the Holy Prophet. The declaration of faith consists of two distinct parts. The absolute belief in the Unity of God and the belief in the Holy Prophet Muhammad as a mortal human being and the Messenger of God.
The second part of the declaration of faith, clarifies that Muhammad (peace be upon him) is the last and final messenger of God. It gives Muhammad the proper title and leadership, and it establishes that he came with the truth and is truthful in regards to the message of His Lord. The most telling attribute of the second declaration is that it disassociates Muhammad (peace be upon him) from God. That Muhammad is not God, and should not be taken as a god. Rather he is the servant and messenger of God and he should be seen simply as that. It also makes obeying and following the advice of the Prophet Muhammad equally important to the belief in Absolute Unity of God.
A person who professes the Declaration of Faith is completely submitting to their selves to the Will of God and that is why one who declares this belief is called a Muslim (one who peacefully completely submits to the will of God).
Once an individual realizes that their Lord is One, and that the message of Islam is indeed true, and they profess the Testimony of Faith all of their previous sins and wrongdoings are forgiven.
The Prophet Muhammad (peace and blessings be upon him) said; “Do you not know that accepting Islam destroys all sins which come before it?” When one accepts Islam, they in essence repent from the ways and beliefs of their previous life. One need not be overburdened by sins committed before their acceptance. The person’s record after becoming Muslim is clean, and it is as if he was just born from his mother’s womb. One should try as much as possible to keep his records clean and strive to do as many good deeds as possible. God has promised paradise for the people leaving this world with this testimony of faith.