After being set free in a noble manner, Thumama (May Allah be pleased with him) became a Muslim and he received a glad tiding of success in this world and hereafter, from the Messenger of Allah ﷺ. He then asked if could proceed to go for Umrah, as he had been on his way to Makkah for Umrah when he was arrested. The Prophet ﷺ allowed him to go for Umrah, but taught him the Islamic way of performing Umrah. When Thumama (May Allah be pleased with him) reached the valley of Makkah, he started reciting Talbiya loudly, "Labbayk Allakumma labbayk. Labbayka laa shareeka laka labbayk. Innal hamda wa-n ni'mata laka wa-l mulk Laa shareeka lak. (Here I am at Your command O Lord, Here I am. Here I am. No partner have You. Here I am. Praise, bounty and Dominion belong to You. No partner have You.") He was thus the first Muslim on the face of the earth to enter Makkah reciting the talbiyah.  The entire Muslim community had migrated to Madinah, so there was no (other) sound of Talibiya and the situation was like a war zone.

When Thumama (May Allah be pleased with him) entered the valley with Talbiya, the Makkan pagans were alarmed and they rushed to him screaming, “Have you too, have left your forefathers’ religion?”

He replied in a very cool manner, “I have not given in," he replied, "but I have decided to follow the best religion. I follow the religion of Muhammad." The agitated Makkan pagans went for him aggressively. Some even wanted to kill him. He shouted, “By Allah! Even if any one (of you) pushes me down then I will take it as an offence. I have discarded idol worship.”

Thumamah (May Allah be pleased with him)  then went on: "I swear to you by the Lord of this House that after my return to al-Yamamah, no grain of wheat or any of its produce shall reach you until you follow Muhammad."  Makkah did not have a fertile land so every grain of food was imported from other parts of Arabiya. The threat worked and Quraish had to keep their hands off him and they stopped each other from harming Thumamah (May Allah be pleased with him).

Under the watchful eyes of the Quraish, Thumamah ibn Uthal (May Allah be pleased with him) performed Umrah as the Prophet ﷺ had instructed him. He dedicated his sacrifice to Allah alone.

Thumamah ibn Uthal (May Allah be pleased with him) returned to his land and promoted Islam amongst his people. Soon all of his people embraced Islam. He then ordered his people to withhold supplies from the Quraish. The boycott gradually began to have an effect and the conditions became more and more harsh. Prices began to rise. Hunger began to bite and there was even fear of death amongst the Quraish. None of them could dare to approach Thumamah and his tribe. So they requested their own leader Abu Sufyan who was still a Non-Muslim, to approach the Prophet ﷺ and request him to release Makkah from the boycott. Abu Sufyan was the biggest enemy of Islam in those days and he was the one who had vowed not to bathe or even oil his hair, till he finished Islam and kill the Messenger of Allah ﷺ. Yet, he knew that the Prophet ﷺ was a humble person with no arrogance and did not have a revengeful attitude.

So he reached Madinah and met the Prophet ﷺ. He informed him of the famine like situation in Makkah due to Thumama’s boycott. The Prophet ﷺ instructed Thumamah (may Allah be pleased with him) to lift the boycott, and so the Makkans started getting their food again.

Thumamah (MayAllah be pleased with him) accepted Islam based upon the knowledge of the humble nature of the Prophet ﷺ and Abu Sufyan , too, approached the Prophet ﷺ with a humble request of mercy towards his people, inspite of being a staunch enemy.

Indeed Character speaks louder than words.