Physical disability was often socially isolating in the ancient world. Mark narrates Jesus' compassionate personal attention to the man in unusual detail.
The crowd's concluding summary of what Jesus accomplishes provides the principal link with Isaiah's restoration promise.
Isaiah 35 announces, 'Behold, your God will come' and promises divine salvation. The signs of that coming include opened blind eyes, unstopped deaf ears, and the tongue of the mute singing for joy.
Mark's description of Jesus making the deaf hear and the mute speak closely evokes that promised restoration.
Jesus takes the man aside, touches his ears and tongue, looks to heaven, and commands, 'Be opened.' The man's hearing and speech are immediately restored.
The crowd responds that Jesus has done all things well and specifically celebrates his making the deaf hear and the mute speak.
The argument is not that healing itself proves deity; biblical prophets also heal.
The significance is that Mark depicts the Isaianic signs of God's saving arrival taking place through Jesus, adding another scriptural layer to the Gospel's divine-identity portrait.
The crowd is astonished beyond measure and proclaims that Jesus makes the deaf hear and the mute speak.