Jesus' power to forgive sins and to cure the sick If one is to answer this question which Jesus  posed to the scribes :  "..For which is easier, to say,  'Your sins are forgiven ', or to say 'Rise and walk' ?... "(Matt. 9:5)  one would opt in favor of the former for an answer. But, Jesus appears to have had the latter option in mind, as is forthcoming from the subsequent narrative. Is it true that the power to forgive sins was entrusted to a limited few, and those who exercised that power without authority were  treated to have committed blasphemy , thereby putting themselves at risk ?
Can someone enlighten me ?
It is not true that others were given the power to forgive sins on the Earth. Only Jesus had that authority. Forgiving sins is not a power it is an authority.

Matthew 21:23 and24 KJV  And when he was come into the temple, the chief priests and the elders of the people came unto him as he was teaching, and said, By what authority doest thou these things? and who gave thee this authority? 24  And Jesus answered and said unto them, I also will ask you one thing, which if ye tell me, I in like wise will tell you by what authority I do these things.

Only God himself can forgive sins, but he gave Jesus the authority to pass that forgiveness to others while on Earth. Jesus explained this relationship in the following passage:

John 5:24 through 30 KJV Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life. 25  Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God: and they that hear shall live. 26  For as the Father hath life in himself; so hath he given to the Son to have life in himself; 27  And hath given him authority to execute judgment also, because he is the Son of man. 28  Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, 29  And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation. 30  I can of mine own self do nothing: as I hear, I judge: and my judgment is just; because I seek not mine own will, but the will of the Father which hath sent me.

Before leaving Earth Jesus gave his disciples certain authority, but not the authority to forgive sins.

Luke 9:1 KJV  Then he called his twelve disciples together, and gave them power and authority over all devils, and to cure diseases. 

Even Peter did not pretend to forgive sin, but professed that the authority to overcome infirmities was of Jesus.

Acts 3:6 KJV Then Peter said, Silver and gold have I none; but such as I have give I thee: In the name of Jesus Christ of Nazareth rise up and walk. 

Acts 4:10 KJV Be it known unto you all, and to all the people of Israel, that by the name of Jesus Christ of Nazareth, whom ye crucified, whom God raised from the dead, even by him doth this man stand here before you whole.

Hope this helps.