Makkans plea to Abu Talib to stop the Prophet(ﷺ)
The Meccans, however, were more than ever furious at the Prophet's (ﷺ) increasing preaching against their religion. They asked his uncle Abu Talib to stop him, but he could not do anything. As the Prophet (ﷺ) persisted in his ardent denunciations against their ungodliness and impiety, they turned him out from the Ka'ba where he used to sit and preach, and subsequently went in a body to Abu Talib.

They urged the venerable chief to prevent his nephew from abusing their gods any longer or uttering any ill words against their ancestors. They warned Abu Talib that if he would not do that, he would be excluded from the communion of his people and driven to side with Muhammad(ﷺ); the matter would then be settled by fight until one of the two parties were exterminated.

Abu Talib neither wished to separate himself from his people, nor forsake his nephew for the idolaters to revenge themselves upon. He spoke to the Prophet very softly and begged him to abandon his affair.

To this suggestion the Prophet(ﷺ) firmly replied:
"O my uncle, if they placed the sun in my right hand and the moon in my left hand to cause me to renounce my task, verily I would not desist therefrom until Allah made manifest His cause or I perished in the attempt."

The Prophet (ﷺ), overcome by the thought that his uncle and protector was willing to desert him, turned to depart. But Abu Talib called him loudly to come back, and he came.
"Say whatever you please; for by the Lord I shall not desert you ever."

Abu Talib protects his Nephew, the Prophet(ﷺ)
The Quraish again attempted in vain to cause Abu Talib to abandon his nephew. The venerable chief declared his intention to protect his nephew against any menace or violence. He appealed to the sense of honor of the two families of the Bani Hashim and the Bani Muttalib, both families being kinsmen of the Prophet, to protect their member from falling a victim to the hatred of rival parties.

All the members of the two families nobly responded to the appeal of Abu Talib except Abu Lahab, one of the Prophet's uncles, who took part with the persecutors.

Umar Al-Khattab submits to Islam
During this period, 'Umar Al-Khattab adopted Islam. In him the new faith gained a valuable adherent and an important factor in the future development and propagation of Islam. Hitherto he had been a violent opposer of the Prophet and a bitter enemy of Islam. His conversion is said to have been worked by the miraculous effect on his mind of a Surah of the Quran which his sister was reading in her house, where he had gone with the intention of killing her for adopting Islam.

Thus the party of the Prophet had been strengthened by the conversation by his uncle Hamza, a man of great valor and merit; and of Abu Bakr and 'Umar, both men of great energy and reputation. The Muslims now ventured to perform their devotions in public.

Quraish divided into two factions
Alarmed at the bold part which the Prophet and his followers were not able to assume, and roused by the return of the deputies from Abyssinia and the announcement of their unsuccessful mission, the Quraish determined to check by a decisive blow any further progress of Islam.

Towards this end, in the seventh year of the mission, they made a solemn covenant against the descendants of Hashim and Muttalib, engaging themselves to contract no marriage with any of them and to have no communication with them. Upon this, the Quraish became divided into two factions, and the two families of Hashim and Muttalib all repaired to Abu Talib as their chief.

Abu Lahab's hatred of Islam
Abu Lahab, the Prophet's uncle, however, out of his inveterate hatred of his nephew and his doctrine, went over to the opposite party, whose chief was Abu Sufyan Ibn Harb, of the family of Umayya.

The persecuted party, Muslims as well as idolaters betook themselves to a defile on the eastern skirts of Mecca. They lived in this defensive position for three years. The provisions, which they had carried with them, were soon exhausted. Probably they would have entirely perished but for the sympathy and occasional help received from less bigoted compatriots.

Reconciliation of the Quraish
Towards the beginning of the tenth year of the mission, reconciliation was concluded between the Quraish and the two families of Hashim and Abdul Muttalib through the intermediation of Hisham, Ibn Umar, and Zobeir, Ibn Abu Umayya. Thus, the alliance against the two families was abolished, and they were able to return to Mecca.

During the period the Prophet and his kinspeople passed in their defensive position, Islam made no progress outside; but in the sacred months, when violence was considered sacrilege, the Prophet used to come out of his temporary prison to preach Islam to the pilgrims.

Death of Abu Talib and Khadijah
In the following year, both Abu Talib and Khadijah died. Thus the Prophet lost in Abu Talib the kind guardian of his youth who had hitherto protected him against his enemies, and in Khadijah his most encouraging companion. She was ever his angel of hope and consolation.

The Prophet, weighed down by the loss of his amiable protector and his beloved wife, without hope of turning the Quraish from idolatry, with a saddened heart, yet full of trust, resolved to exercise his ministry in some of her field. He chose Taif, a town about sixty miles east of Mecca, where he went accompanied by a faithful servant Zaid.

The tribe of Thakif (Thaqif), who were the inhabitants of Taif, received Muhammad (ﷺ) very coldly. However, he stayed there for one month. Though the more considerate and better sort of men treated him with a little respect, the slaves and common people refused to listen to his teachings; they were outrageously indignant at his invitation to abandon the gods they worshipped with such freedom of morals and lightness of heart. At length they rose against him, and bringing him to the wall of the city, obliged him to depart and return to Mecca.

People of Madina accept Prophet
The repulse greatly discouraged his followers; however, the Prophet boldly continued to preach to the public assemblies at the pilgrimage and gained several new converts, among whom were six of the city of Yathrib (later called Medina), of the Jewish tribe of Khazraj.
When these Yathribites returned home, they spread the news among their people that a prophet had arisen among the Arabs who was to call them to Allah and put an end to their inquiries.

Reference: From "Stories of the Prophets" by Al-Imam ibn Kathir