Jesus probably did not want a big crowd to witness the miracle; he wanted to avoid the crowd’s acclaim.1 This is not the only time that this happens in the Gospel according to Mark.
Furthermore, this healing was an act of mercy and grace
in the ministry of Jesus. It was not meant to be a sign to all the onlookers that Jesus was the Son of God. However, to us as readers this miracle, together with the other miracles that Jesus performed, all point us to Jesus as the Son of God.2
Some also say that by taking the man aside, Jesus shows that he sees the man as a unique individual.3
33 And taking him aside from the crowd privately, he put his fingers into his ears, and after spitting touched his tongue.