Muhammad in his entire life time undertook unlimited battles and fought some eight of them.  When we ask these things to an Islamic scholar that why the Prophet of Most Peaceful religion fought so many battles, their instant reply will be that these battles which Muhammad undertook and fought were all in self defense. Some Scholars even say that “not a single battle was offensive, or he (Muhammad) fought because Allah informed his messenger with the help of Archangel Gabriel that the Non-Believers were plotting and planning against him to kill him.”
But how can we trust these Scholars without going through the evidence of their claim. So in this article we will see that whether really Muhammad fought his battles in Self Defense or were offensive battles. Lets start with the Battle of Badr.
Battle of Badr
This battle took place when Muhammad commanded some his men to go to the place called Nakhlah, which is situated between Makkah and At-Ta ‘ if and asked them to lie in wait for Quraish and bring their news. When these Muslims on command of Muhammad reached Nakhlah, they found a caravan of Quraish, which passed from near by.  The Quraish men in that Caravan were Amr Ibn Al-Hadrami, Uthman Ibn Abdullah, and his brother Naufal, and Al-Hakam Ibn Kaisan. When the Muslims saw these Quraish with their Caravan, they decided to attack them in the Prohibited month, and one of Muslim named Waqid Ibn Abdullah shot Al-Hadrami. Uthman Ibn Abdullah and Al-Hakim were captured and Naufal was successful in escaping from Muslims.
When Muhammad came to know that his followers have looted the Caravan in prohibited month and killed one of the Quraish, he denied to take anything from the Loot. On this Allah suddenly revealed a verse, which is Qur’an Ch 2 Verse 217, which reads:-
They ask you about the sacred month – about fighting therein. Say, “Fighting therein is great [sin], but averting [people] from the way of Allah and disbelief in Him and [preventing access to] al-Masjid al-Haram and the expulsion of its people therefrom are greater [evil] in the sight of Allah . And fitnah is greater than killing.” And they will continue to fight you until they turn you back from your religion if they are able. And whoever of you reverts from his religion [to disbelief] and dies while he is a disbeliever – for those, their deeds have become worthless in this world and the Hereafter, and those are the companions of the Fire, they will abide therein eternally.
One of the famous commentator of Qur’an, Ibn Jalalayan says on this verse:-
Thus the Prophet (s) sent forth the first of his raiding parties under the command of ‘Abd Allāh b. Jahsh. They fought against the idolaters and killed [‘Amr b. ‘Abd Allāh] Ibn al-Hadramī in [the sacred month of] Rajab, thinking that it was the last day of Jumādā II. The disbelievers reviled them for making fighting lawful in a sacred month, and so God revealed the following: They ask you about the sacred, the forbidden, month, and fighting in it (qitālin fīhi, ‘fighting in it’, is an inclusive substitution [for al-shahri l-harāmi, ‘the sacred month’]). Say, to them: ‘Fighting (qitālun is the subject) in it is a grave thing (kabīr, ‘grave’, is the predicate), that is, heinous in terms of sin; but to bar (saddun is the subject), people, from God’s way, His religion, and disbelief in Him, in God, and, to bar from, the Sacred Mosque, that is, Mecca, and to expel its people, the Prophet (s) and the believers, from it — that is graver (the predicate of the [last] subject), [that is] more heinous in terms of sin than fighting in it, in God’s sight; and sedition, your idolatry, is graver than, your, slaying’, in it. They, the disbelievers, will not cease to fight against you, O believers, until, so that, they turn you from your religion, to unbelief, if they are able; and whoever of you turns from his religion, and dies disbelieving — their, good, works have failed, that is, they are invalid, in this world and the Hereafter. Thus they will not count for anything and will not result in any reward. The specification of death as a condition is because if that person were to return to Islam [again], his original deeds would not be invalidated, and he will be rewarded for them, and he would not have to repeat them, [deeds] such as [performing] the Pilgrimage: al-Shāfi‘ī is of this opinion. Those are the inhabitants of the Fire, abiding therein. [Source]
Here we see how Allah justifies killing of Quraish in prohibited month by saying that Non-Believers were the first to bar the way of Allah and were the reason of Fitna, but when we look in to the historical context of the verse, we can clearly see that this verse was revealed only for Muhammad. As he denied to accept the booty, because his companions killed people of Quraish in prohibited month and the Jews and people of Quraish started opposing him and considering it as a bad omen.  So Muhammad took help of his lord, and made him justify killing of Al-Hadrami, so that he can take the 1/5 part of the war booty. ( As mentioned in Qur’an Ch 8 Verse 1)
So we see the background of the fight and it cannot be said that Muslims fought a defensive fight, as we clearly see that Muslims were the first to attack, kill and loot the Caravan and people of Quraish. After this incident Ibn Ishaq says, that Messenger of Allah heard Abu Sufyan Ibn Harb was coming from Syria, with large Caravan of Quraish, containing their money and merchandise, accompanied by some thirty or forty men. The Messenger of Allah summoned the Muslims and said,
“This is caravan of Quraish which contains their money. Go out to attack it; perhaps Allah will give it as a prey.” 
When Abu Sufyan came to know about Muhammad’s plan, he hired Damdam Ibn ‘Amr to go to Mecca to order Quraish to come out to save their property from Muhammad and his companions. In this context Ibn Kathir relates Bukhari narrating a hadith, Vol 5, Book 59, No 286, which reads:-
Abu Jahl addressed Sa`d saying, “I see you wandering about safely in Mecca inspite of the fact that you have given shelter to the people who have changed their religion (i.e. became Muslims) and have claimed that you will help them and support them. By Allah, if you were not in the company of Abu Safwan, you would not be able to go your family safely.” Sa`d, raising his voice, said to him, “By Allah, if you should stop me from doing this (i.e. performing Tawaf) I would certainly prevent you from something which is more valuable for you, that is, your passage through Medina.” On this, Umaiya said to him, “O Sa`d do not raise your voice before Abu−l−Hakam, the chief of the people of the Valley (of Mecca).” Sa`d said, “O Umaiya, stop that! By Allah, I have heard Allah’s Apostle predicting that the Muslim will kill you.” Umaiya asked, “In Mecca?” Sa`d said, “I do not know.” Umaiya was greatly scared by that news. When Umaiya returned to his family, he said to his wife, “O Um Safwan! Don’t you know what Sa`d told me? “She said, “What has he told you?” He replied, “He claims that Muhammad has informed them (i.e. companions that they will kill me. I asked him, ‘In Mecca?’ He replied, ‘I do not know.”Then Umaiya added, “By Allah, I will never go out of Mecca.” But when the day of (the Ghazwa of) Badr came, Abu Jahl called the people to war, saying, “Go and protect your caravan.” But Umaiya disliked to go out (of Mecca).
So it is clear by the above authentic narration that Quraish fought the battle of Badr to protect their property from looters and raiders of Prophet Muhammad.People of Quraish answered the call of Damdam and got ready to protect their property and money. On this occasion Quraish men said, “Do Muhammad and his companions think this is going to be like Caravan of Ibn Hardami.” All most every man of Quraish went to fight Muhammad and his companions for saving their property.
This was the background of Muhammad’s fight of Badr and according to the evidence from canonical scriptures and biography of Muhammad we can now say without the shadow of Doubt that this fight of Muhammad was not defensive, but was very offensive. He tried to loot the caravans of Quraish and in that process his companions even killed some Quraish men and looted their property. Quraish fought back to protect their property and that too when Muhammad again tried to to loot their caravan. In this case Quraish were defensive, not Muhammad.
Now this is sufficient evidence to prove that Muhammad was a Looter, a Thug, and we can also discard the claim that he led a peaceful and simple life. We will see his other fights in second part of this article.
 Battles of the Prophet by Ibn Kathir. Page No – 1 to 3
 IBID, Page No- 4 to 5
 Muhammad The Messenger of Allah, by Muhammad Ridha, Page No – 207
 Battles of the Prophet by Ibn Kathir. Page No – 7
 Ibid, Page No – 12