About some prisoners of the battle of Badr who had become Muslims, there remained a doubt that they, once back in Makkah, may turn away from Islam and start hurting them thereafter. In the next verse (71), Allah Ta` ala has removed this apprehension by saying: وَإِن يُرِيدُوا خِيَانَتَكَ فَقَدْ خَانُوا اللَّـهَ مِن قَبْلُ فَأَمْكَنَ مِنْهُمْ ۗ وَاللَّـهُ عَلِيمٌ حَكِيمٌ ﴿71﴾ (And if they intend to commit treachery against you, then, they have already committed treachery against Allah, so Allah has given [ you ] power over them. And Allah is All-Knowing, Wise). It means that should these people decide to commit a breach of trust with you, it will not bring any hurt or loss to you. They were the same people who had already committed a breach of trust with Allah. They had admitted of Allah being the Lord of all the worlds at the time of the original Covenant, then they became hostile to it. But, this breach of trust turned out to be fatal for none but them when, finally, they were disgraced and detained. As for Allah Ta` ala, He is the knower of secrets hidden in hearts, and He is the possessor of great wisdom. If these people start opposing you even now, there is nowhere they can go, certainly not anywhere outside the range of the power and control of Allah Ta` ala. Inevitably, He shall seize them as before. To sum up, it can be said that, in verse 70, the da'wah of Islam was given to the released prisoners in the mode of persuasion - while in verse 71, it was in the mode of warning that they were told that success in their worldly life and in their life to come depends on Islam and 'Iman.
Upto this point, the text was dealing with injunctions relating to fighting and killing disbelievers, taking them prisoners, setting them free and carrying on peace negotiations with them. In verses which follow right upto the end of the Surah itself, a particular related chapter has been taken up alongwith some details of its injunctions. They are the injunctions of Hijrah (Emigration) - because, situations can arise during a confrontation with disbelievers wherein neither the Muslims have the power to launch an attack against them and kill them off, nor are they willing to go for peace. In such a state of weakness, the only course through which Islam and Muslims can be salvaged is Hijrah (Emigration) which means that Muslims should leave that city or country and go to stay in some other land where acting freely in accordance with Islamic injunctions is possible.