Here two questions arise:

1. Was the Prophet Muhammad (peace and blessings be upon him and his family) a monotheist before receiving his prophetic mission?
2. According to which religion did he worship before the beginning of his mission?

The following discussion addresses both questions.

The Prophet's Faith in Allah and His Monotheism Before the Mission

Historical evidence—alongside rational and theological arguments—clearly demonstrates that before Allah commissioned him with Islam, the Prophet (peace and blessings be upon him and his family) firmly believed in the One Allah. He was a monotheist who never worshipped an idol or bowed before a statue. This is regarded as an established and undisputed fact.

Although this matter is as evident as the sun itself, it is worthwhile to mention some authentic historical reports so that this consensus is reinforced by reliable historical evidence.

As for his dislike of idols and avoidance of pagan worship, authentic historical accounts include the following:

1. His Rejection of Amulets in Childhood

A lengthy narration states that when the Prophet was three years old, he asked his foster mother, Halimah al-Sa'diyyah:

"Why do I not see my two brothers during the day?"

She replied:

"My son, they are tending the sheep."

He asked:

"Why do I not go out with them?"

She said:

"Would you like that?"

He answered:

"Yes."

The next morning, Halimah says that she anointed him with oil, applied kohl to his eyes, and hung around his neck a Yemeni amulet. The child immediately removed it and said:

"Please, Mother, do not do that. I have One who protects me."

2. His Conversation with the Monk Bahira

During his first journey to Syria with his uncle Abu Talib, the monk Bahira said to the young Muhammad:

"Young man, I ask you by al-Lat and al-'Uzza to answer my questions."

The Messenger of Allah replied:

"Do not ask me by al-Lat and al-'Uzza. By Allah, I have never hated anything more than those two."

Bahira then said:

"Then I ask you by Allah."

The Prophet answered:

"Ask whatever you wish."

3. His Refusal to Swear by Pagan Deities

It is narrated that during his second trading journey to Syria with Maysarah, Khadijah's servant, a dispute arose between the Prophet and another merchant after the goods had been sold.

The man said:

"Swear by al-Lat and al-'Uzza."

The Prophet replied:

"I have never sworn by them. Whenever I pass by them, I deliberately turn away."

Another version records him saying:

"Away from me! May your mother lose you! The Arabs have never spoken a phrase more hateful to me than those words."

The man then replied:

"Your word is accepted."

He later told Maysarah:

"By Allah, this man is a prophet."

His Worship of Allah Before Revelation

Historians unanimously agree that the Prophet (peace and blessings be upon him and his family) would retire every year to the Cave of Hira for an entire month to worship Allah.

Imam Ali ibn Abi Talib (peace be upon him) described this period by saying:

"Every year he would withdraw to Hira. I alone would see him, while no one else saw him."

It was there, during one of these retreats, that the Angel Gabriel first brought him the divine revelation.

The authors of the six major Sunni collections of hadith likewise report:

"He used to withdraw to Hira and devote himself to worship there for a number of nights."

Imam Ali also described this stage of the Prophet's life:

"From the time he was weaned, Allah assigned to him the greatest of His angels to guide him day and night along the path of noble character and the highest virtues."

His Pilgrimages Before the Mission

Reports also state that the Messenger of Allah performed several pilgrimages before the beginning of his mission, carrying out the rites correctly and away from the attention of Quraysh.

Imam Ja'far al-Sadiq (peace be upon him), in a narration transmitted by Ibn Abi Ya'fur, said:

"The Messenger of Allah performed ten pilgrimages secretly."

Another narration states:

"Twenty pilgrimages."

The secrecy was necessary because Quraysh had altered certain rites of Hajj and 'Umrah, performed the pilgrimage incorrectly, and at times changed the sacred months for political and economic reasons—a practice known as al-Nasi' (intercalation).

These and many other historical incidents provide compelling evidence of the Prophet's faith and monotheism. How could a man raised in such a pure household, under the guidance of an angel appointed by Allah to nurture and direct him, have deviated from the path of pure monotheism?

Furthermore, there is no doubt that the final Messenger (peace and blessings be upon him and his family) is superior to all previous prophets, as affirmed by the Qur'an.

The Qur'an also states that some prophets attained prophethood while still children.

For example, regarding John (Yahya), son of Zechariah, Allah says:

"O John! Hold fast to the Scripture." And We granted him wisdom while he was still a child.
(Qur'an 19:12)

Likewise, concerning Jesus ('Isa), son of Mary, who spoke while still in the cradle after the Israelites questioned Mary's miraculous childbirth, the Qur'an records him saying:

"Indeed, I am the servant of Allah. He has given me the Scripture and made me a prophet. He has made me blessed wherever I may be and has enjoined upon me prayer and charity as long as I live."
(Qur'an 19:30–31)

Thus, Jesus proclaimed his faith, prophethood, and the fundamentals of religion while still an infant.

Can any fair-minded person accept that John and Jesus openly professed faith in Allah from childhood, yet the greatest of all prophets remained without faith or monotheism until the age of forty—despite the fact that he was engaged in worship in the Cave of Hira when the Angel of Revelation first descended upon him?