Generate a delicately shaded and vibrant digital art image, depicting a solemn biblical scene. Show two sons named Isaac and Ishmael, of differing descents; one Middle-Eastern and the other Caucasian, in mourning attire, solemnly burying their father in a cave. Set this scene in a field known as Machpelah, filled with dry vegetation and rocky terrain. Incorporate an indication in the artwork that the land is owned by Ephron, a character of Hittite descent, in the form of an old, robust stone marker. The background should show the light fading, indicating this location is 'before Mamre'. Keep the focus on the emotional aspect.