"A double minded man is unstable in all his ways." (James 1: 8)
I used to read this verse, and think that I had to make sure that I was thinking righteous, pure thoughts.
Later, I learned about the different minds that a man may have:
"For to be carnally minded is death; but to be spiritually minded is life and peace.
"Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be.
"So then they that are in the flesh cannot please God." (Romans 8: 6-8)
Are we double-minded when we sin? No, we are double-minded to the degree that we think that we must do something in order for God to move in our lives.
The writer in Hebrews spelled out the New Covenant clearly:
"For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people:
"And they shall not teach every man his neighbour, and every man his brother, saying, Know the Lord: for all shall know me, from the least to the greatest.
"For I will be merciful to their unrighteousness, and their sins and their iniquities will I remember no more." (Hebrews 8: 10-12)
The New Covenant makes everything of God through His Son Jesus and nothing of us. In fact, before we received Him into our lives, we had nothing:
"And you hath he quickened, who were dead in trespasses and sins;
"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:" (Ephesians 2: 1-2)
Christ is our Life (Colossians 3: 4), and He is the Author and Finisher of faith itself (Hebrews 12: 2), and by His faith we live (Galatians 2: 20)
Now, no one should read the above and then think that we have nothing to do, or that we are left with being empty shells:
"Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling.
"For it is God which worketh in you both to will and to do of his good pleasure." (Philippians 2: 12-13)
He works in us and through us and for us that He may make Himself manifest in us.
When we doubt that God has taken care of everything through His Son, when we conclude that we must do something, then we fall from grace (Galatians 5: 4).
"Carnal mind" is more than a sinful mind, but rather a mind which does not believe and take in all the good which God has, is, and will keep on doing through His Holy Spirit:
It's all about believing on Him! Not on Jesus and our parents, or Jesus and our political parties, or Jesus and our own efforts. Not one thing, person, place, or idea belongs or holds place with Christ Jesus.
"But when Jesus heard it, he answered him, saying, Fear not: believe only, and she shall be made whole." (Luke 8: 50)
and
"As soon as Jesus heard the word that was spoken, he saith unto the ruler of the synagogue, Be not afraid, only believe." (Mark 5: 36)
and
"Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent." (John 6: 29)
But believing on Christ Jesus brings in more, and means so much more:
"Jesus cried and said, He that believeth on me, believeth not on me, but on him that sent me." (John 12: 44)
and
"Who is he that overcometh the world, but he that believeth that Jesus is the Son of God?" (1 John 5: 5)
If He has overcome all things, and in Him we receive all things (Romans 8: 31-32), then what do you have to doubt about?