Mitch Chase outlines three purposes of the miracles of Christ:

‘First, miracles provoke identity questions about Jesus. In Mark 4:35–41, where Jesus calmed the tumultuous waves and wind, the disciples said, “Who then is this, that even the wind and the sea obey him?” (4:41).

Second, miracles bear witness to the origin and truthfulness of Jesus’s ministry. They are works that “bear witness about me that the Father has sent me” (John 5:36).

Third, miracles foreshadow the far-future age of worldwide shalom. God had promised in the Old Testament that his future work in the world would bring transformation and restoration to creation and to his creatures (Isa 35:1–10). Jesus’s miracles were glimpses of the glorious life to come for God’s people and God’s world.’

(Emphasis added)