The poem main subject is to point out that Christians who hold their beliefs can do great things and even if they fall they will welcome to heaven by angels on their way there.
The song tells of how Charlemagne a Christian king, wanted to conquer the Muslim king Marsile (Project Gutenberg) in Stanza I line  the poem states “Marsile its King, who feareth not Gods name” Meaning that they felt being Muslim equated to being evil that has to be uprooted. For seven years king Charlemagne had been at war with the Saracens and only King Marsile and queen Bramimonde of the city of Saragossa had not been defeated. The poem gives a parallel of a battle between the good and the evil. In this the Saracens are presented as evil and the Franks present the pure good, their major motivation being doing the will of God. According to the poem the Saracean who are Muslims on dying their souls are bound for the eternal flame of hell.
The fighters are greatly motivated by their religious beliefs .The fighters in this song have very strong Christian conviction believing that God’s will comes before any man and God is a kind God and all powerful. For example in deciding the fate of the traitor Ganelon they go for a judicial fight with faith that God will intervene for the right man. Ironically that is what happened when Thierry a brave but less physically built than Ganelon manages to slay Ganelon in the fight.
The fighters have strong sense of duty and loyalty both to God and their fellow fighters. Because of Roland’s sense of duty he fought to death at the pass of Roncevaux together with twenty thousand Christians against an army of four hundred thousand men. This same loyalty mad King Charlemagne to avenge the death of Roland. This kind of duty and loyalty that arose spontaneously could be parallel to the love of God. In such a holly war fighters considered it being bound by duty and loyalty to each other as divine.