Illustration of a Christian parable from Genesis 18-31, depicted with the finesse, elegance, and realism typical of the Renaissance era, avoiding any form of text or words. This religious narrative should be treated with reverence, expressing a sense of devotion. The serene backdrop should resemble the Italian countryside, featuring rolling hills and a cloud-streaked azure sky, while Abraham, portrayed as a Middle-Eastern man, and the three heavenly visitors, this time represented by a Caucasian man, a South Asian man, and a Black man, hold a sacred conversation. Please exclude any disrespectful elements.