Jesus came not for the purpose of healing the sick.
Healing is temporary because all those who are healed still eventually die.
We all die because we all sin.
Ezekiel 18:20 The soul that sinneth, it shall die...
Romans 6:23 For the wages of sin is death...
Jesus’ came to save us from death itself which is a consequence of our sins.
John 1:29 The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.
This he did by fulfilling the Law, living a life without sin and voluntarily giving his life for the remission of our sins.
John 15:13 Greater love hath no man than this, that a man lay down his life for his friends. 14 Ye are my friends, if ye do whatsoever I command you.
Matthew 26:28 For this is my blood of the new testament, which is shed for many for the remission of sins.
Acts 10:43 To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins.
Romans 5:8 But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us.
1 Corinthians 15:3 For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;
The miracles of healing that Jesus did were a sign from God that the gospel that Jesus preached was from God.
John 10:38 though ye believe not me, believe the works: that ye may know, and believe, that the Father is in me, and I in him.
The man born blind to whom Jesus gave sight understood the implication.
John 9:30-33 The man answered and said unto them, Why herein is a marvellous thing, that ye know not from whence he is, and yet he hath opened mine eyes. 31 Now we know that God heareth not sinners: but if any man be a worshipper of God, and doeth his will, him he heareth. 32 Since the world began was it not heard that any man opened the eyes of one that was born blind. 33 If this man were not of God, he could do nothing.
The Jews in the main who saw the miracles of healing still would not believe that Jesus was the promised Messiah.
John 12:37 But though he had done so many miracles before them, yet they believed not on him:
All who do not believe him die in their sins and perish forever.
John 8:24 I said therefore unto you, that ye shall die in your sins: for if ye believe not that I am he, ye shall die in your sins.
Acts 4:12 Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.
If Jesus had healed all the sick in the world it would have had no lasting benefit.
The healing was the sign that forgiveness of sins come through Christ.
Matthew 9:5 For whether is easier, to say, Thy sins be forgiven thee; or to say, Arise, and walk? 6 But that ye may know that the Son of man hath power on earth to forgive sins...
He preached the gospel of the kingdom of God which if believed and obeyed will result in our resurrection from the dead to eternal life when Christ returns. Only by belief of the gospel and baptism into Christ can we have eternal salvation.
Mark 16:15 And he said unto them, Go ye into all the world, and preach the gospel to every creature. 16 He that believeth and is baptized shall be saved; but he that believeth not shall be damned (condemned).
By his life of obedience and self denial even unto death, Jesus made it possible for us to attain to eternal life at the resurrection of the dead. Set against this, temporary healing is of little worth; it has no lasting benefit.
May God bless you,