Banu Bakr attacked Banu Khuza' at night and killed innocent men. Banu Khuza' reported the matter to the Holy Prophet (ﷺ) in Medina. The Quraish, in the meantime, realized their mistake and Abu Sufyan hastily reached Medina to approach the Holy Prophet (ﷺ) but the Holy Prophet (ﷺ) told him that the Makkans had to choose one of the three options; to pay the blood money; to break their alliance with Banu Bakr or to declare that the treaty stood dissolved.
The Quraish could not accept the first two conditions and therefore, the Holy Prophet (ﷺ) began secret preparations to march toward Makka. He raised an army of about 10,000 troops and marched towards Makka in January 630/Ramadan 8AH. The army in- included the Muhajireen, the Ansar, and several Bedouin tribes of northern Arabia. The army camped at Marr az Zahran, northeast of Makka, and the Quraish were taken aback when they saw 10,000 torches on the hills at night. Abu Sufyan immediately approached the Holy Prophet (ﷺ) and submitted to Islam after a lot of negotiations.
The next morning, the Holy Prophet (ﷺ) divided his army into four columns with a head of each. The first column was under his command; the second was under Abu Ubaidah bin al-Jarrah (رضی اللہ تعالیٰ عنہ); the third was under Saa'd bin Ubaadah (رضی اللہ تعالیٰ عنہ) and the fourth was under Khalid bin Waleed (رضی اللہ تعالیٰ عنہ). Each was strictly instructed not to attack unless it was attacked.
The Holy Ka'ba, the house of Abu Sufyan, and one's own house were declared as places of safety. Accordingly, the Muslim army entered quite peacefully and untacked except for Khalid's army. The Holy Prophet (ﷺ) approached the Holy Ka'ba, performed its Tawaf, and then purified it from all the idols. He recited this verse while destroying the idols:
"Say truth has prevailed and falsehood perished; for
falsehood is bound to perish." (17:81).
After this, he declared a general amnesty for all his insultors
and enemies except for a few only. He stayed in Makkah for about twenty days,
defined the boundaries of Haram, and made other similar arrangements before leaving
for Medina.