1250 The emphasis is on the first clause: it is only when the four months of grace are past, and the other party shows no signs of desisting from its treacherous designs by right conduct, that the state of war supervenes - between Faith and Unfaith.
1251 When war becomes inevitable, it must be prosecuted with vigour. According to the English phrase, you cannot fight with kid gloves. The fighting may take the form of slaughter, or capture, or siege, or ambush and other stratagems. But even then there is room for repentance and amendment on the part of the guilty party, and if that takes place, our duty is forgiveness and the establishment of peace.
1252 The repentance must be sincere, and that is shown by conduct - a religious spirit of true prayer and charity. In that case we are not to bar the gate against the repentant. On the contrary we must do all we can to make their way easy, remembering that Allah is Oft-Forgiving, Most Merciful.
4 i.e., inside or outside the sanctuary of the Sacred House in Mecca.