Having attained puberty, the Shaikh traveled to Makkah and then to Medina to learn from learned personalities there. Then he went to Iraq (Basrah) to seek after knowledge. It was in Iraq that he started his mission. There he called the people to Tawheed and the Sunnah of the Prophet (صلى الله علیه وسلم). He announced that it was the duty of every Muslim to follow his or her religion (Islam) strictly in accordance with the Qur'aan and the Sunnah. He engaged in debates and discussion with scholars and thus became famous. However, some characterless scholars rebelled against him and he faced some harms and persecutions from them. So, he left Basrah moving towards Az-zubair, then to al-Ahsa, and then finally to Huraymela, where also he faced much suffering at the hands of the wicked because he enjoined the good and forbade the evil and perSauded the rulers to punish the criminals severely. So, some of them even attempted on his life, but Allaah saved him. Then he moved to Oyayna, which was then governed by Prince Uthman Ibn Muhammad Ibn Muammar, who welcomed the Shaikh with hospitality and promised him all support and help in calling people to Islam.
People in Najd at that time lived in a condition that could not be approved by any believer. Polytheism had spread widely; people worshiped domes, trees, rocks, caves or any persons who claimed to be Awliya (saints). Magic and soothsaying also had spread. When the Shaikh saw that polytheism was dominating the people and that no one showed any disapproval of it or no one was ready to call people back to Allaah, he decided to labor singly and patiently in the field. He knew that nothing could be achieved without Jihad, patience and suffering.
The Shaikh continued calling people to the Path of Allaah and guided them to piety, righteousness and love in the cause of Allaah. Gradually, the Shaikh became famous in and around Oyayna. People came to Oyayna to meet him from neighboring areas and villages. He also wrote to many scholars requesting their support and reminding them of their task of helping Allaah's Religion and fighting against polytheism. Many scholars from Najd, Makkah and al-Medina accepted his request, while some disagreed with him, reproached his mission, condemned him and kept him away.
The Shaikh and those with him were in between two types of people; one group consisted of the ignorant people, who knew nothing about Islam and followed deviations and innovations, superstitions, etc. which their forefathers had upheld. The Qur'aan says about them, "We found our fathers following a certain way and religion and we will indeed follow their footsteps." The second group, on the other hand, was related to knowledge but responded negatively to the Shaikh because of their envy and also because they were ashamed and afraid that the people would question their integrity, 'why did you keep silent without warning us against such and such evils until Abdul Wahhab appeared?'
But the Shaikh carried on patiently seeking the Help of Allaah in all matters. He strove hard in studying the Qur'aan and reading useful books. He had a special skill of interpreting the Qur'aan and deducing from it. He also worked hard in studying the life of the Prophet (صلى الله علیه وسلم) and the lives of his companions (رضي الله عنهم).
The Shaikh went on teaching and preaching. Gradually, he exerted himself on practically removing polytheism when he noticed that his call to Islam had no affect on some. One day, the Shaikh said to the governor,
'Let us demolish the dome at the grave of Zaid Ibn al-Khattab (رضي الله عنه) (Zaid Ibn al-Khattab was the brother of Umar Ibn al-Khattab (رضي الله عنهم) and a martyr, who died in the fighting against Musailimah Khaddhab in 12 A.H, he was buried and later on people built a dome on his grave). It is erected on deviation and the Prophet (صلى الله علیه وسلم) has forbidden building domes or mosques on graves. Moreover, this dome has destroyed the people's belief with polytheism. So, it must be demolished.'
The Prince agreed and mobilized an army of six hundred soldiers and marched towards the grave, headed by the Shaikh. As soon as they approached the dome, the people came forward to defend it but when they saw the Prince with his army, they changed their decision. Then the Shaikh took the action of demolishing and removing the dome. Allaah removed it by his hands and Al-hamdulillah, none of its traces remains now. Similarly, there were other domes, caves, trees, etc. that were also destroyed and removed. The Shaikh, thus, continued his mission by words and action, for which he became very famous. Also, one day a woman came to him and confessed that she had committed adultery. After realizing that she was sane, married and had confessed without external compulsion, he gave the order according to the Sunnah that she should be stoned to death as a punishment, as he had now become the Judge of Oyayna.
Meanwhile, the Prince of al-Ahsa (and surrounding villages) feared the Shaikh's position, because committing wrong, robbery, murder, etc, were usual for them. He wrote to Prince Uthman threatening him and demanding him to kill the Shaikh. The Prince approached the Shaikh saying,
"the nomad prince has sent me a message to do so and so. We never wish to kill you, but we are afraid of the prince and we are unable to fight him. So if you think you may leave."
The Shaikh replied:
"I am simply calling people to Islam and to the fulfillment of the testimony of Faith that there is no god except Allaah and Muhammad is Allaah's Messenger. Whoever holds fast to Islam and upholds it truthfully, Allaah will help him and make him ruler of his enemy's countries. And if you endure and be righteous and accept this Religion, then be glad that Allaah will help you and protect you from the nomad prince and others. Allaah will also give you power over his country and his kinfolk."
But Uthman said:
"O Shaikh! But we cannot fight him nor can we stand his oppression."
So, the Shaikh had to leave Oyayna for Dareyya on foot because Uthman did not even provide him any means of transportation.
On reaching Dareyya, the Shaikh stayed in the house of a man who was one of the best personalities in Dareyya, but he feared the prince of Dareyya, Muhammad Ibn Saud. The Shaikh said to him,
'be glad and hope for the best. I am simply calling the people to Allaah's Religion, and He will undoubtedly make it victorious.'
The news of Shaikh's arrival in Dareyya reached Muhammad Ibn Saud. It is said that his wife first informed him of the Shaikh. She was a kind and pious lady and she addressed her husband saying,
'Here is a great fortune sent to you by Allaah. A man who is calling the people to Islam, calling to the Qur'aan and the Sunnah of the Prophet (صلى الله علیه وسلم). What a good fortune! Rush to him and support him. Never resist him or stop him from that.'
Muhammad Ibn Saud accepted her advice and went to the Shaikh and made a contract with the Shaikh that he should not leave the country.
The Shaikh now settled in Dareyya. People started to come to him for learning from everyplace - from Oyayna, Iraq, Manfooha, Riyadh and other neighboring places. Respected, loved, supported by the people, the Shaikh arranged lectures on various topics; Creed, the Holy Qur'aan, the Qur'aanic commentaries, Islamic Jurisprudence and its principles, the Hadeeth and its terminology, and others. He arranged classes for the public as well as for the selected persons. Thus, he continued his mission and activities of preaching in Dareyya. He wrote to the scholars and rulers establishing his arguments and warning them against polytheism and innovation. Because of his correspondence with scholars and rulers and his struggling in the cause of Allaah, the Shaikh became famous. His mission continued and spread all over the Islamic world and also other countries.
It is a known fact that every favour has its envier, as every preacher has his enemies. Allaah, the Exalted, said in the Qur'aan:
"And so We have appointed to every Prophet an enemy - devils among the men and Jinn - inspiring to each other adorned speech as a delusion. And had your Lord willed they could not have done it. So, leave them alone to their fabrication." [Soorah al-An'aam (6): 112]
When the Shaikh became famous for his teaching, and his writings received wide popularity among the people, many envious groups emerged as his opponents. One group consisted of characterless scholars who saw the truth as falsehood and falsehood as truth, and believed that building domes and invoking the engraved as pertaining to Islam. The second group was associated with knowledge but was ignorant of the reality of the Shaikh's mission. They simply believed others and kept aloof from the Shaikh. The third group that opposed the Shaikh consisted such people who feared the removal of their positions and ranks. They showed humility so that the supporters of the Islamic mission might not reach them and remove their positions and take over their lands.
So, some opposed him in the name of religion, while other opposed him in the name of politics though they hid under the cover of knowledge and religion and exploited the enmity of those scholars who had hated him and accused him of deviation. Sometimes, his opponents argued that he belonged to the Khawarij, at times some criticized him out of their lack of proper knowledge, etc. Thus, the fighting between words continued through debates and arguments. He would write to them and they would reply to him, and he would refute them, and thus numerous questions and answers were accumulated and compiled into volumes. And Al-hamdulillah, most of them have been published. Then the Shaikh turned to Jihad in 1158 A.H, he wrote to people to enter the field of Jihad and remove polytheism, which existed in their countries.
The Shaikh, thus, strove in his preaching and Jihad for fifty years from 1158 A.H. until he died in 1206. He resorted to all methods of his mission - Jihad, preaching, resistance, debates and arguments until people adhered to obedience and demolished the domes and mosques built by them on the graves and agreed to run their affairs in accordance with Islamic Law, discarding all rules and laws which had been applied by their fathers and forefathers. Then after the death of the Shaikh, his sons, grandson and supporters continued his mission and struggle in the cause of Allaah.