What is an overview of Protestants' answers to why I still sin when I have the Spirit of God in me? If we, as Christians and believers, are indwelt with the perfect and true Holy Spirit, the same spirit of Jesus, which is also the fullness of God, why do we still sin?


  Galatians 4:4-7 ESV But when the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” So you are no longer a slave, but a son, and if a son, then an heir through God.


This passage led me to a debate within myself that went like this:


  
  Q: If we have the Spirit of Jesus in us, why do we sin?
  A: We sin because we're in the flesh. (Romans 7)
  Q: Then how come Jesus didn't sin while being in the flesh?
  A: Because Jesus was God. Because Jesus had perfect faith. Because he was perfectly obedient. (Philippians 2) 
  Q: But if we're given the same Spirit that Jesus had upon believing, the same Spirit as God, why can't we do any of those things? Why do we still sin?
  A: ???
  


A good answer will show how biblical sources would be utilized by the various Protestant denominations to address the questions listed above.
If I have the Spirit of Jesus in me, why do I still sin?

Jesus did not sin because he had a different father than the rest of us. His father was God.


  Luke 1:35  And the angel answered and said unto her, The Holy Ghost
  shall come upon thee, and the power of the Highest shall overshadow
  thee: therefore also that holy thing which shall be born of thee shall
  be called the Son of God.


Our physical connection to Adam means that sin reigns in our flesh.


  1 Corinthians 15:21-22  For since by man came death, by man came also
  the resurrection of the dead.   For as in Adam all die, even so in
  Christ shall all be made alive.


Being freed from the compelling power of sin means that we have the possibility of living by the Spirit free from the influence of sin.


  Romans 6:11-14  Likewise reckon ye also yourselves to be dead indeed
  unto sin, but alive unto God through Jesus Christ our Lord.   Let not
  sin therefore reign in your mortal body, that ye should obey it in the
  lusts thereof.  Neither yield ye your members as instruments of
  unrighteousness unto sin: but yield yourselves unto God, as those that
  are alive from the dead, and your members as instruments of
  righteousness unto God.   For sin shall not have dominion over you:
  for ye are not under the law, but under grace.


Any of us who are honest can relate to the frustration of Paul as he reflects of the difficulty of trying to keep the law by the power of his flesh in Romans chapter seven.


  Romans 7:15  For that which I do I allow not: for what I would, that
  do I not; but what I hate, that do I.


In chapter eight Paul shifts dramatically talking about the victory the Christian who walks by the power of the Spirit has.


  Romans 8:4-5  That the righteousness of the law might be fulfilled in
  us, who walk not after the flesh, but after the Spirit.   For they
  that are after the flesh do mind the things of the flesh; but they
  that are after the Spirit the things of the Spirit.


There are many people who intensely deny that any Christian can demonstrate carnality (the flesh). They would say that any demonstration of sin indicates that a person is not a Christian. When pressed on this declaration, they often rephrase it as any demonstration of "gross sin". 

There are Christians who fail to mature and become as fruitful as they could or as the Lord would have them.


  1 Corinthians 3:1-3  And I, brethren, could not speak unto you as unto
  spiritual, but as unto carnal, even as unto babes in Christ.   I have
  fed you with milk, and not with meat: for hitherto ye were not able to
  bear it, neither yet now are ye able.   For ye are yet carnal: for
  whereas there is among you envying, and strife, and divisions, are ye
  not carnal, and walk as men?


There are Christians who are overtaken by sin.


  Galatians 6:1-2  Brethren, if a man be overtaken in a fault, ye which
  are spiritual, restore such an one in the spirit of meekness;
  considering thyself, lest thou also be tempted.   Bear ye one
  another's burdens, and so fulfil the law of Christ.


There are Christians following the course of the world.


  James 4:4  Ye adulterers and adulteresses, know ye not that the
  friendship of the world is enmity with God? whosoever therefore will
  be a friend of the world is the enemy of God.


Satan has set the course of this world.


  Ephesians 2:2  Wherein in time past ye walked according to the course
  of this world, according to the prince of the power of the air, the
  spirit that now worketh in the children of disobedience:


He has designed the world to resonate with the flesh. 


  1 John 2:16  For all that is in the world, the lust of the flesh, and
  the lust of the eyes, and the pride of life, is not of the Father, but
  is of the world.


Jesus warned even his disciples about leaven (teachings) that were dangerous.


  Matthew 16:11  How is it that ye do not understand that I spake it not
  to you concerning bread, that ye should beware of the leaven of the
  Pharisees and of the Sadducees? 
  
  Mark 8:15  And he charged them, saying, Take heed, beware of the
  leaven of the Pharisees, and of the leaven of Herod.


The three groups cited each had a worldly characteristic. The Pharisees believed that they had achieved their own righteousness. The Sadducees believed they had inherited their righteousness. The Herodians were not so much interested in righteousness but in political and economic power and influence. These are all influences that can enter the life of a Christian and spread like leaven until the Christian is spiritually immobilized and made ineffective. 

It is difficult to reach a carnal Christian. He is both limited in his capacity to understand and is often disinterested in the things of the Lord. 

The original question might be more accurately stated as "If I now have the Spirit of Jesus in me, why do I still sin as much as I do?"

Because our physical bodies still have their connection to Adam, we will have the influence of the flesh. This influence can be magnified by any of the following;


Our entanglement with the world.
Our habits and values developed from childhood.
The teachings of our church.
The imprint of the world we receive from TV, work, and school.
The influence of those with whom we associate.
Our comforts and conveniences.
Our divided loyalties (Christ versus 401K, health care, savings account, good job, etc.)


Like the rich young ruler there is often much that we cannot let go of. 


  Luke 18:24-27  And when Jesus saw that he was very sorrowful, he said,
  How hardly shall they that have riches enter into the kingdom of God! 
  For it is easier for a camel to go through a needle's eye, than for a
  rich man to enter into the kingdom of God.   And they that heard it
  said, Who then can be saved?   And he said, The things which are
  impossible with men are possible with God.


There is a point where the sinful influence of the flesh will no longer be felt.


  1 Corinthians 15:54  So when this corruptible shall have put on
  incorruption, and this mortal shall have put on immortality, then
  shall be brought to pass the saying that is written, Death is
  swallowed up in victory.