The Meaning of Shahadatan or the Two Declarations of Faith
The Meaning of Shahadatan or the two declarations of Faith
In fact, Islam is the religion of Allah with which He (Glorified be He) sent the Messengers (peace be upon them) and revealed the books in order to call for it. Allah revealed the Glorious Qur'an with this aim and the authentic Sunnah of the Prophet (peace be upon him) also aims at this. The greatest and most obligated duty is to know this fact and know the religion of Allah to worship Allah Alone which is the meaning of the two declarations of faith, namely, there no one worthy of worship but Allah and that Muhammad is Allah's Messenger.
The Prophet (peace be upon him) called people and guided them to this fact. He (peace be upon him) said, I have been ordered to fight against the people until they testify that none has the right to be worshipped but Allah and that I am the Messenger of Allah. And He (peace be upon him) said, I have been ordered to fight against the people until they testify that none has the right to be worshipped but Allah. If they say it, then they save their lives and property from me unless otherwise legally required.
Whoever testifies, out of faith, will observe the other pillars and thereby he/she admits him/herself to worship, which is the mission for which he is created.
Therefore, he/she should abide by the declarations of faith and believe in all that Allah and His Messenger told about the preceding Messengers and the revealed Books as well as what Allah said in His Book about Paradise, Hell, the Last Day, and all of this is included in the concept of `Ibadah and Iman. The call to establishing Tawhid is, in fact, a call to the entire religion as the person who believes in the Oneness of Allah and becomes devoted to him is required to fulfill what Allah prescribed on him and to avoid what Allah forbids.
The duties and the prohibitions are branches and integrated parts to this basis. The most required, premier, and most important thing is to establish Tawhid and devotion to Allah, and to avoid Shirk.
Owing to this importance and status, the Prophet (peace be upon him) started with these matters in the people of Makkah and other places. He (peace be upon him) used to call people to these matters at first along with believing in him as Allah's Messenger. After that, he would tell them about other matters of Islam such as Salah (prayer) and other acts of worship.
When he (peace be upon him) sent Mu`adh (may Allah be pleased with him) to Yemen, he (peace be upon him) said to Mu`adh, You will go to a group from the People of the Book, so call them to testify that there is no one worthy of worship but Allah and that I am the Messenger of Allah. Another narration mentions, Invite them to worship Allah alone. If they obey you in doing so, tell them that Allah has enjoined upon them five prayers during the day and night.
The Prophet (peace be upon him) ordered him to call them at first to establish Tawhid, devotion to Him, seeking Him Alone with worship, and avoiding Shirk.
Accordingly, this is the first duty and it is, in the meantime, the worship for which Allah created people. He (Exalted be He) said, And I (Allâh) created not the jinn and mankind except that they should worship Me (Alone).
(Part No. 7; Page No. 90 - 91)
Fatawa Sheikh Abdul Aziz Ibn Baz