Yeshua could have healed the man by any means that he wanted to, so why did he use spittle. You will notice that he took the man by the hand which speaks of the fact that it is God who chooses who will “see.” He then leads him away from the “village”, which symbolizes the world. You will see a similar story in Mark 7.33 where there is a deaf man and Yeshua also took the man aside, away from the others.
This is necessary because we are chosen by God and then he separates us from the world. We are all “blind and deaf” before the Lord separates us. We were chosen in him before the foundation of the world (Eph 1.4). In both stories he uses “spittle”, which comes from his mouth, which speaks of his Word. We are cleansed by the washing of his Word. Yeshua touches the tongue of the man in Mark 7.33 and this alludes to the application of his testimony.
Spittle also refers to a person’s “strength” as seen in Psa 22.15. In Mark 8.23-26 we see that Yeshua applied the spittle to the man’s eyes but the healing was not immediate. Yeshua lays his hands again on the man in v 25 and he begins to see clearly. This tells us that the Basar (Gospel) and salvation comes in power and it dispels the darkness of the mind and gives “light” to the believer. This light is small at first but gradually the person will gain full insight. So, in both stories, Yeshua is using spittle, which comes from his mouth, which speaks of the power of his Word to deliver the person so that they can see and hear spiritually.