I think when we write an essay about literature, we use 'present tense' no matter if the literature itself is in past tense. But for example, "Ben suddenly recalled his high school life. When he was in the ninth grade, he was very popular. But now, he was not. He was such an ordinary man. No one would notice him." Then, if I want to say his past, should I use past tense to make a contrast with present tense, so that reader will understand which is Ben's past life, and which is his present? Let's say: Ben always remembers his glory in high school, he was/is a such popular student. Teachers loved him/love him. However, now he is not well-liked by his boss or co-workers.
When events occur before the point of the narrative you are dealing with, use the past tense IMO.