" Jesus’ emotional state was so intense that it says “…his sweat was as it were great drops of blood falling down to the ground.” The “sweat” is the Greek word idros. The word “drops” is the Greek word thrombos, a medical word that points to blood that is unusually thickly clotted. When these two words are joined, they depict a medical condition called hematidrosis — a condition that occurs only in individuals who are in a highly emotional state. Because the mind is under such great mental and emotional pressure, it sends signals of stress throughout the human body. These signals become so strong that the body reacts as if it were under actual physical pressure. As a result, the first and second layer of skin separate, causing a vacuum to form between them. Thickly clotted blood seeps from this vacuum, oozing through the pores of the skin. Once the blood seeps through, it mingles with the sufferer’s sweat that pours from his skin as a result of his intense inner struggle. In the end, the blood and sweat mix together and flow down the victim’s face like droplets to the ground. "

― Rick Renner , Sparkling Gems from the Greek: 365 Greek Word Studies for Every Day of the Year to Sharpen Your Understanding of God's Word