“Jesus took him aside from the crowd, by himself, and put His fingers into his ears, and after spitting, He touched his tongue with the saliva; and looking up to heaven with a deep sigh, He said to him, ‘Ephphatha!’ that is, ‘Be opened!’ and his ears were opened, and the impediment of his tongue was removed, and he began speaking plainly” (Mark 7:32-35). “Taking the blind man by the hand, He brought him out of the village; and after spitting on his eyes and laying His hands on him, He asked him, ‘Do you see anything?’ and he looked up and said, ‘I see men, for I see them like trees, walking around.’ Then again He laid His hands on his eyes; and he looked intently and was restored, and began to see everything clearly” (Mark 8:23-25). “When He had said this, He spat on the ground, and made clay of the spittle, and applied the clay to his eyes, and said to him, ‘Go, wash in the pool of Siloam’ (which is translated, Sent). So he went away and washed, and came back seeing” (John 9:6-7).
Why is Jesus spitting on people? This is not something that we would do today. Most people would rub an oil on it and call it good. Jesus uses spit. Spitting on someone is clearly offensive (Matt. 26:67; 27:30). Why would Jesus use spit when on other occasions He healed people just by speaking?
During that time, spit was considered to have healing properties, especially for blindness. The Jews wrote of it in the Palestinian Talmud (collection of Jewish traditions), and Pliny (61-113 A.D.) wrote about it in his Historia Naturalis. The Gentile and Jew alike attested to the healing powers of saliva. Jesus could have used that common belief to aid in the healing aspect of the miracle and to create in the person receiving the healing a certain expectation of being healed.
A more likely possibility has to do with another Jewish tradition. This tradition states that if a birthright is contested, with more than one man claiming to be the firstborn, then a test was given. The one whose saliva healed someone first would be considered the firstborn son. In turn, this suggested that the spit of the firstborn son was the most potent in its healing properties. So, when this is laid beside John chapters 8 and 9, we see a larger picture unfolding. In John 8, Jesus is nearly stoned when He asserts that He is the Son of God and God Himself. The events of chapter 9 seem to be a continuation of chapter 8. Jesus said that the healing of the blind man was to glorify God (9:3-5). By healing this man, He showed again that He was sent by God and that God had sent His firstborn son. So, what appears to be a strange practice is more of a testimony to the authority that God had given Him. Jesus was masterful at using the moments and opportunities presented to Him to teach great truth.