The believers who failed to join the Ghazwa of Badr and those who took part in it are not equal (in reward).  

أَنَّهُ سَمِعَهُ يَقُولُ {لاَ يَسْتَوِي الْقَاعِدُونَ مِنَ الْمُؤْمِنِينَ} عَنْ بَدْرٍ وَالْخَارِجُونَ إِلَى بَدْرٍ