Allah said,

﴿وَلَقَدْ نَصَرَكُمُ اللَّهُ بِبَدْرٍ﴾

(And Allah has already made you victorious at Badr,)﴿3:123﴾ meaning, during the battle of Badr, which occurred on a Friday, the seventeenth of Ramadan, in the second year of Hijrah.

The day of Badr is known as Yawm Al-Furqan ﴿the Day of the Clarification﴾, by which Allah gave victory and dominance to Islam and its people and disgraced and destroyed Shirk, even though the Muslims were few. The Muslims numbered three hundred and thirteen men, with two horses and seventy camels. The rest were foot soldiers without enough supplies for the battle. The enemy army consisted of nine hundred to a thousand men, having enough shields and supplies, battle-ready horses and even various adornments.

However, Allah gave victory to His Messenger , supported His revelation, and illuminated success on the faces of the Prophet and his following. Allah also brought disgrace to Shayatan and his army. This is why Allah reminded His believing servants and pious party of this favor,

﴿وَلَقَدْ نَصَرَكُمُ اللَّهُ بِبَدْرٍ وَأَنتُمْ أَذِلَّةٌ﴾

(And Allah has already made you victorious at Badr, when you were a weak little force), cwhen you were few then. This Ayah reminds them that victory is only from Allah, not because of a large army and adequate supplies. This is why Allah said in another Ayah,

﴿وَيَوْمَ حُنَيْنٍ إِذْ أَعْجَبَتْكُمْ كَثْرَتُكُمْ فَلَمْ تُغْنِ عَنكُمْ شَيْئاً﴾

(. .and on the day of Hunayn (battle) when you rejoiced at your great number, but it availed you naught) ﴿9:25﴾, until,

﴿وَاللَّهُ غَفُورٌ رَّحِيمٌ﴾

(And Allah is Oft-Forgiving, Most Merciful) ﴿9:27﴾.

Badr is an area between Makkah and Al-Madinah and is known by the well that bears its name, which in turn was so named after Badr bin An-Narayn, the person who dug the well.

﴿فَاتَّقُواْ اللَّهَ لَعَلَّكُمْ تَشْكُرُونَ﴾

(So have Taqwa of Allah that you may be grateful.) ﴿3:123﴾, means, fulfill the obligations of His obedience.

﴿إِذْ تَقُولُ لِلْمُؤْمِنِينَ أَلَنْ يَكْفِيكُمْ أَن يُمِدَّكُمْ رَبُّكُمْ بِثَلاَثَةِ ءَالاَفٍ مِّنَ الْمَلَـئِكَةِ مُنزَلِينَ - بَلَى إِن تَصْبِرُواْ وَتَتَّقُواْ وَيَأْتُوكُمْ مِّن فَوْرِهِمْ هَـذَا يُمْدِدْكُمْ رَبُّكُمْ بِخَمْسَةِ ءَالافٍ مِّنَ الْمَلَـئِكَةِ مُسَوِّمِينَ - وَمَا جَعَلَهُ اللَّهُ إِلاَّ بُشْرَى لَكُمْ وَلِتَطْمَئِنَّ قُلُوبُكُمْ بِهِ وَمَا النَّصْرُ إِلاَّ مِنْ عِندِ اللَّهِ الْعَزِيزِ الْحَكِيمِ - لِيَقْطَعَ طَرَفاً مِّنَ الَّذِينَ كَفَرُواْ أَوْ يَكْبِتَهُمْ فَيَنقَلِبُواْ خَآئِبِينَ - لَيْسَ لَكَ مِنَ الاٌّمْرِ شَىْءٌ أَوْ يَتُوبَ عَلَيْهِمْ أَوْ يُعَذِّبَهُمْ فَإِنَّهُمْ ظَـلِمُونَ ﴾

﴿وَللَّهِ مَا فِى السَّمَـوَتِ وَمَا فِى الاٌّرْضِ يَغْفِرُ لِمَن يَشَآءُ وَيُعَذِّبُ مَن يَشَآءُ وَاللَّهُ غَفُورٌ رَّحِيمٌ ﴾

(124. (Remember) when you said to the believers, "Is it not enough for you that your Lord should help you with three thousand angels sent down'') (125. "But, if you hold on to patience and have Taqwa, and the enemy comes rushing at you; your Lord will help you with five thousand angels having marks (of distinction).'') (126. Allah made it not but as a message of good news for you and as an assurance to your hearts. And there is no victory except from Allah, the All-Mighty, the All-Wise.) (127. That He might cut off a part of those who disbelieve, or expose them to infamy, so that they retire frustrated.) (128. Not for you is the decision; whether He turns in mercy to (pardon) them or punishes them; verily, they are the wrongdoers.) (129. And to Allah belongs all that is in the heavens and all that is in the earth. He forgives whom He wills, and punishes whom He wills. And Allah is Oft-Forgiving, Most Merciful.)