Great literature is both timely and timeless. When we study ancient literature or that from other cultures, we learn much about the context surrounding the work--in other words "timely." But great works are also timeless. They appeal to all generations. They have an universal appeal. Shakespeare, for instance, deals with love, corruption, jealously, war, prejudice, ambition--all topics that are relevant to people of today.
One quick look at the Anglo Saxon "The Seafarer" and the Victorian "Dover Beach" shows the idea of timely and timelessness. Both concern the sea, suffering, and spiritual faith and a world perspective. The events that surrounded these two poems are vastly different--the decline of a warrior society versus the publication of Darwin's Origin of the Species. Yet, we can see through each work the struggle of the author to come to terms with his world and his faith while viewing the awesomeness of the sea.
Studying both ancient literature and more contemporary works provides us a better understanding of our own world and those elements that link us together as humans.