Arthur is the symbol of the ardour and strength of God's grace.Consider the role of Arthur in Book 1 of The Faerie Queene.

In Cantos Seven and Eight, after hearing about Una's plight, Arthur takes on the role of her champion against Orgoglio. In the end, he vanquishes his opponent by dismemberment and befriends Redcrosse.

In Canto Seven, Una's happenstance meeting with Prince Arthur introduces this pivotal character to the epic. Prince Arthur is, of course, the young King Arthur, mythical past and destined future ruler of Britain. Arthur steps in to fulfill the role left vacant by Redcrosse, but he does it as part of his larger quest to find the Faerie Queene. 

In Canto Eight, Prince Arthur triumphs where Redcrosse failed, for he is not prideful. Arthur’s attack on Duessa’s mount may be a reference to his virtuous assault on the foundations of Roman Catholicism, or perhaps even a political cry for a leader to champion Protestantism over Catholicism in Spenser’s own day. Arthur is victorious over Orgoglio and wins Redcrosse’s freedom.

Redcrosse begins his rehabilitation by facing the truth. He must look upon Duessa’s true form that he may never forget the true nature of deceit (particularly the theological deceit of Roman Catholicism).

In Canto Nine, Prince Arthur’s tale of his own quest for the Faerie Queene foreshadows his own involvement in the epic (had it been completed), and although he and Recrosse become friends and exchange gifts, Arthur goes on his way to complete his quest leaving the others behind.