Erec and Enide displays the themes of love and chivalry that Chrétien continues in his later work. Tests play an important part in character development and marital fidelity. Erec's testing of Enide is not condemned in the fictive context of the story, especially when his behaviour is contrasted with some of the more despicable characters, such as Oringle of Limors. Nevertheless Enide's faithful disobedience of his command to silence saves his life.
Another theme of the work is the Christianity, evidenced by the plot's orientation around the Christian Calendar. When Erec first sets off, it is Easter, at Pentecost he marries Enide, and his coronation occurs at Christmas. Furthermore, in the poem, Erec is killed and then resurrected on a Sunday, an allusion to the story of Jesus Christ.
In the 12th century, conventional love stories tended to have an unmarried heroine, or else one married to a man other than the hero. This was a sort of unapproachable, chaste courtly love. However, in Erec and Enide, Chrétien addressed the less conventionally romantic (for the time period) concept of love within marriage. Erec and Enide marry before even a quarter of the story is over, and their marriage and its consequences are actually the catalysts for the adventures that comprise the rest of the poem.