Why would Jesus touch the blind man twice to heal him, surely He had the power to heal him right the first time. So, it would appear to me that there is some significance for why this healing happened this way. Though, in this as with all Scripture we must remember that the hidden things belong to the LORD but the things that have been revealed belong to us (Deut. 29:29). Thus, we cannot take all of the mystery out of this passage but we can offer a few reasons for why this miracle went down as it did (Remember Jesus could have done it much differently cf. Matt. 9:27-31; Jn. 9:1-12). Here is the text under question:
And they came to Bethsaida. And some people brought to him a blind man and begged him to touch him. And he took the blind man by the hand and led him out of the village, and when he had spit on his eyes and laid his hands on him, he asked him, “Do you see anything?” And he looked up and said, “I see people, but they look like trees, walking.” Then Jesus laid his hands on his eyes again; and he opened his eyes, his sight was restored, and he saw everything clearly. And he sent him to his home, saying, “Do not even enter the village.” (Mark 8:14-26)
As with any passage, the context must be considered. This is a cursory look at the passage but we should be able to get at a the reason for the double healing. So in the broad context of the New Testament and the Gospels there is quite a lot about spiritual seeing. In Mark chapter four Jesus explains His use of parables. He said (see Mk. 4:10-12) I use parables “so that ‘they may indeed see but not perceive, and may indeed hear but not understand, lest they should turn and be forgiven’” to recall Isaiah (Is. 6:9-10).
In the immediate context in chapter 8 we see that Jesus talks about “seeing” i.e. understanding. He says, “Having eyes do you not see, and having ears do you not hear? And do you not remember? When I broke the five loaves for the five thousand, how many baskets full of broken pieces did you take up?” They said to him, “Twelve.” “And the seven for the four thousand, how many baskets full of broken pieces did you take up?” And they said to him, “Seven.” And he said to them, “Do you not yet understand?’” (Mk. 8:18-21).
After this the disciples and Jesus (“they”) went to Bethsaida (Mk. 8:22). So there was some time that elapsed between verse 21 and verse 22 in historical reality. Yet Mark places the healing of the blind man directly following the conversation between Jesus and the disciples.
Why? And why such a strange healing? Why would Jesus spit in the blind man’s eyes and yet not completely heal him? Why would he still have poor sight (Mk. 8:24)? Why would Jesus have to touch him again (Mk. 8:25)?
Based on the context I think it reminds us of the disciples and their vision. They “see” i.e. understand but their understanding is still very poor. They too will need a second touch. Notice what follows this passage. Jesus asks His disciples, “What do you say that I am?” Peter as the disciples typical spokesman said, “You are the Christ.”
Jesus is essentially asking the disciples, “Do you see, do you understand?” The disciples respond, “Yes, we see you are the Christ.” Yet, they did not know but they didn’t see as clearly as they thought they did. They saw “men , but they look like trees,” you could say (Mk. 8:24). This is proven later especially by the once very vocal Peter as he denies Jesus (Mk. 14:66-72). He truly did not see what it meant for Jesus to be the Christ. He too needed a second touch. He too needed to be healed of his blindness.
Thus I think in retrospect the healing of the blind man in this passage is a type of parable. Jesus asked, “Having eyes do you not see, and having ears do you not hear? And do you not remember?” (Mk. 8:18). The disciple did see and yet they did not see. It is a strange paradox. They had in a sense been healed as the blind man but their vision, their understanding, was still a long way off. Their vision would not be fixed until they saw the Lord again and He fixed them (Mk. 16:12-14). At the end of Luke after Jesus’ resurrection we see that Jesus gave the disciples the correct understanding of the Christ that they lacked (Lk. 24:27, 44-47). After this lens adjustment they could see clearly.
So why was the blind man healed twice? I think to teach something about the disciples. It appears that way to me based on the immediate context of the passage and the way that blindness and seeing is used in Scripture.