Series of 4 lectures which Khalil Jaffer talks about the 'Obstacles to Knowing God'

The Basis of these lectures is the verse 111 of Sura Tawba:

إِنَّ اللّهَ اشْتَرَى مِنَ الْمُؤْمِنِينَ أَنفُسَهُمْ وَأَمْوَالَهُم بِأَنَّ لَهُمُ الجَنَّةَ يُقَاتِلُونَ فِي سَبِيلِ اللّهِ فَيَقْتُلُونَ وَيُقْتَلُونَ وَعْدًا عَلَيْهِ حَقًّا فِي التَّوْرَاةِ وَالإِنجِيلِ وَالْقُرْآنِ وَمَنْ أَوْفَى بِعَهْدِهِ مِنَ اللّهِ فَاسْتَبْشِرُواْ بِبَيْعِكُمُ الَّذِي بَايَعْتُم بِهِ وَذَلِكَ هُوَ الْفَوْزُ الْعَظِيمُ

Surely Allah has bought of the believers their persons and their property for this, that they shall have the garden; they fight in Allah's way, so they slay and are slain; a promise which is binding on Him in the Taurat and the Injeel and the Quran; and who is more faithful to his covenant than Allah? Rejoice therefore in the pledge which you have made; and that is the mighty achievement. (less info)