Someone who wishes to call other people to Islam has to be prepared to deal with those who are stubborn, rude, and downright insulting in their opposition to Islam and its message. This is one of the reasons why patience and tolerance are indispensable qualities for a Muslim preacher.
Persistence is another. No matter how much hostility and rudeness someone might exhibit when hearing about Islam, it is a mistake for a Muslim preacher to consider anyone a "lost cause."
Allah is the one who opens up our hearts to faith and to His guidance. He makes the most stubborn and reluctant of hearts receptive to His message. We see this in history, especially in the stories of the Prophets. Tufayl b. `Amr al-Dawsī used to place cotton in his ears to prevent him from hearing Prophet Muhammad’s words. Then he said to himself: “I am a well-grounded individual who can discern what is good from what is bad. By God! I will hear what he has to say. If it is right, I will accept it, and if not I will shun it.” The very first time he listened to the Prophet’s message, he believed in it and accepted it.
Then there was `Umar b. al-Khattāb, a man possessed of strength and a severe manner. He used to abuse the believers in Mecca in the early days of Islam. He finally resolved himself upon killing the Prophet Muhammad (peace be upon him). On his way to do that grave deed, he learned that his sister had accepted Islam. Enraged, he changed course and headed for her house. In the altercation that ensued, he struck his sister, drawing blood. Regretful and shocked by what he did, `Umar calmed down, and his sister persuaded him to hear the Qur'an, which he did.
He then returned to his search for Prophet Muhammad (peace be upon him), knocking on the door of al-Arqam b. Abī al-Arqam, where the Prophet was staying – but now `Umar was intent upon declaring to him that he had embraced Islam. `Umar then openly declared his faith in front of all the people. From that day forth, he was unwavering in His belief, devout in prayer, and humble before his Lord.
This was how so many people came to Islam. `Ikrimah, the son of Abū Jahl fled from Prophet Muhammad (peace be upon him) when Mecca was taken peacefully. During his flight, Allah chose to make his journey a journey of faith. `Ikrimah returned to Mecca to a believer and became one of the pre-eminent members of the Muslim community, honored in history for his courage, his sacrifice, and ultimately his martyrdom.
We see the same pattern throughout history, and up to the present day. Those who are the most sinful or who show the most hostility towards Islam, after Allah opens up their hearts with the light of faith, become the strongest of believers.
I have personally known a number of people who were rebellious, arrogant and disdainful about religion, who reformed themselves to the point where most of us could only hope to be more like them. Glory be to Allah who changes people’s hearts for the better.