In the ninth year after the Emigration (630 AD), news reached Madina that Byzantine Emperor Heraclius had begun preparations for war against the Muslims, gaining the support of allied Arab Christian tribes such as the Banu Lakhm, Djudham, ‘Amila and the Ghassan. Upon hearing of this, Prophet Muhammad started to make preparations for battle, despite the prevailing drought and famine. His aim was to quell enemy assault on-site and thwart potential danger. Information regarding battle preparations of the Muslims in the Qur’an (see: at-Tauba, 9:38-106) and in sources of Islamic history reveal that the Byzantines – who gained certain dominance over the Sassanids – were viewed as a very serious force by the Muslims. Despite the fact that the Prophet generally kept secret the destination of military expeditions, on this occasion he openly announced that the objective this time was the Byzantine army; this was because the road to be travelled was long and the enemy large and powerful. In addition, the weather was extremely hot and it was time for harvest.

During preparations, many Companions, first and foremost ‘Uthman, made significant contributions to the armament of the Muslim army. Providing 1,000 steeds, ‘Uthman also equipped 10,000 soldiers, spending one gold coin on each. 'Abd al-Rahman ibn al-'Awf and Talha ibn Zubayr made significant donations. ‘Umar gave half of his wealth and Abu Bakr all of it. Virtually everyone did all that they could in way of supporting the Muslim army.

Alongside the earnest, altruistic and committed Muslims were, as with every other campaign, the hypocrites who stopped at nothing to cause mischief and discord. Reminding the Muslims of Byzantine power, they claimed that setting off on a campaign in such drought and famine was senseless and, like so, tried to dishearten the Muslims. In contrast, there were also those sincere Muslims who were too poor to find steeds, shedding tears because they were unable to participate.

Prophet Muhammad set out from Madina with an army constituting the largest of his time –30,000 men, 10,000 of whom were cavalry – reaching Tabuk, which was 600 kilometers north of Madina on the road to Syria, and setting up base there (Rajab 9/October 630). They camped there for fifteen to twenty days, but there was no sign of the Byzantine army. During his stay at Tubuk, Prophet Muhammad sent units, westbound, for the purpose of conveying Islam to Jarba', Eila, Adhruh, Maqna, and Ma’an, spread across a vast geographical area and with majority Christian and some Jewish populations. Their representatives stated that they would not accept Islam but would pay the poll tax (jizya); as such, they accepted the status of being citizens of the Muslim state under the condition that their lives, property and freedom of belief were secured. Prophet Muhammad had separate treaty documents written out for each of these places and handed these to them. Meanwhile, the military unit of 400 men led by Khalid ibn Walid was dispatched to Duwmat al-Jandal, an important center on the Iraq route. Khalid captured the Duwmat al-Jandal fortress and taking the Christian ruler Ukaydar ibn ‘Abd al-Malik who displayed hostility towards the Muslims as prisoner, took him to Prophet Muhammad. The Prophet made a pact with Ukaydar on the condition that he would pay the poll tax and permitted him to return to his land. In this way, the Duwmat al-Jandal people’s acceptance of the sovereignty of the Muslim state by paying the jizya was ensured.

It is reported that Prophet Muhammad staying in Tabuk at the time, sent a second letter of invitation to Heraclius, who was said to be in either in Emessa or Dimashq (Damascus), with Dihyah ibn Khalifah al-Kalbi. In the letter, the three alternatives of accepting Islam, paying jizya or fighting were proposed to the Emperor, with him being also requested to at least not prevent those from among his people who wanted to accept Islam from doing so. Receiving the letter, the Emperor consulted with his religious and military officials and thereafter sent an envoy, a member of the Christian Arab tribe the Banu Tanuh, to Prophet Muhammad. The envoy was welcomed as much as the conditions would allow and he was presented expensive clothing as a gift by ‘Uthman.

The Tabuk Campaign, the last campaign that the Prophet himself attended, constituted a great test for the Muslims and, on the basis of the Qur’anic verse stating that it was undertaken in a “time of hardship” (saat al-‘usra) (At-Tauba, 9:117), the army taking part in this campaign were referred to as the “army of hardship” (jaysh al-‘usra). There are many verses in the Qur’an which discuss the attitude of those Muslims who participated in the campaign or who did not participate, either with legitimate reason or not, as well as the attitude of the hypocrites who tried to dissuade those wanting to take part (See: At-Tauba, 9:38-106; 117-118).

When Prophet Muhammad returned to Madina from the Tabuk Campaign, he went to the Prophet’s Mosque and after praying the Prayer of Thankfulness, he accepted the felicitations of those who were unable to participate. He also appeared to accept the congratulations of the hypocrites who had offered myriad excuses for not attending. In actual fact, they were making up false excuses and were lying (At-Tauba, 9:94-97). Ka’b ibn Malik, one of Prophet Muhammad’s famous poets and veterans of Badr, Hilal ibn Umayya and Marara ibn ar-Rabi’ missed the campaign without a justifiable excuse despite their favorable financial condition and good health. The three came to the Prophet and owned up with regards to their situation. His displeasure evident in his demeanor, the Prophet told them to leave and wait until God revealed His judgment; he prohibited other Muslims from speaking or meeting with them and after a while the ban was extended to their wives. Being reduced to this position proved to be unbearable for them. They were unable to go out into society and face people because of their shame. Such was the level of their remorse. They did not eat or drink anything for days on end and begged God for forgiveness. Finally, the Qur’anic verses that were revealed after a boycott of 50 days described their spiritual state during this entire process and declared that God had forgiven them and accepted their repentance (At-Tauba, 9:118). This Divine pardon greatly pleased these three Companions first and foremost, as well as Prophet Muhammad and the other Muslims. Ka’b ibn Malik wanted to donate the entirety of his wealth to the poor due to the acceptance of his repentance; however, the Prophet told him that it would be better for him to retain a certain portion of it for himself. Keeping only his land in Khaybar, Ka’b gave the rest away.

One of the things that Prophet Muhammad did upon his return from Tabuk was to destroy the building – referred to as the Mosque of Dirar (Dissension) – constructed by the hypocrites as an operational based from which to conspire against the Muslims. During the time at which the Prophet was preoccupied with final preparations for the Tabuk Campaign, a group from among the hypocrites came to the Prophet and told him that they had built a mosque where the elderly, ill and disabled could pray on rainy and cold nights and asked him to officially open the building for worship by leading the prayer there himself. Specifying that he was about to set off on campaign, he stated that he could only lead the prayer on his return. On his return from Tabuk, when Prophet Muhammad camped at Dhu Awan with his army, some of the hypocrites came to him and wanted to take him to their mosque, for him to lead the prayer therein. During this time, verses pertaining to the so-called mosque and the intentions of those who established it were revealed (At-Tauba, 9:107-110). Declaring those who built the mosque to be liars, these verses stressed that their actual intention was unbelief, to harm the believers and to cause dissension among them. Moreover, being called the Mosque of Dissension, the verses forbid the Prophet from praying there and decreed that it would be more fitting for him to pray in the mosque founded upon piety and reverence for God, that is, in the Prophet’s Mosque. As such, when it became clear that the building in the guise of a mosque was a center of conspiracy and sedition against the Muslims, Prophet Muhammad assigned two Companions to destroy it.