If Jesus is so powerful (i.e. can perform powerful miracles) and loves all people, then why did he not save all people through a miracle?

Answer: The formulation of the question betrays that the reader has apparently not taken into sufficient consideration that God created humans, above all, as creatures with a free will. This is the immeasurable distinction between human beings and other created beings. Only a creature with free will can really respond to God in love. God could enforce all manner of things by a powerful miracle but God created man in His wisdom – created in His own image – so that He cannot force humankinds response of love truly and freely given. The drama of Gods history with humankind is that from the beginning God respects free will. Mary, the mother of Jesus the Messiah, was the first person, who, healed by Jesus Christ in the power of the Holy Spirit, responded to God the Father in completely free and total love through her unconditional Yes. Her sinless Yes was the fruit of her sons obedience, obedience even to the cross.