Dr. E: Astounding. The fact you dismiss this core belief of Christianity positions yourself outside the church of God and contrary to God's word...again "For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's." -- 1 Corinthians 6:20
And the Lord said "go, and from now on sin no more." (cf. John 8:11) Yes, He paid for our sins, but we are now obliged to sin no more. Without His sacrifice none had a chance to be saved. With His sacrifice the whole world has a chance to be saved.
For, as soon as He said "sin no more," He adds "Whoever follows me will never walk in darkness, but will have the light of life." [ John 8:12 ]
Truly, as Dr. Eckleburg has shown, we are purchase of God - bought for a price. Here again is that beautiful passage she posted:
For by one offering he hath perfected for ever them that are sanctified. [Whereof] the Holy Ghost also is a witness to us: for after that he had said before, This [is] the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them; And their sins and iniquities will I remember no more. Now where remission of these [is, there is] no more offering for sin. Hebrews 10:14-18
Our first treasure is the Light Himself Who brings forth His own fruit which counts for treasure to us.
In him was life; and the life was the light of men. John 1:4
A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things. Matthew 12:35
He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water. (But this spake he of the Spirit, which they that believe on him should receive: for the Holy Ghost was not yet [given]; because that Jesus was not yet glorified.) John 7:38-39
But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, Meekness, temperance: against such there is no law. Galatians 5:22-23
And those whose names have not been blotted out (Revelation 3:5) will receive their reward their treasure and crown.
Blessed [is] the man that endureth temptation: for when he is tried, he shall receive the crown of life, which the Lord hath promised to them that love him. James 1:12
Jesus said unto him, If thou wilt be perfect, go [and] sell that thou hast, and give to the poor, and thou shalt have treasure in heaven: and come [and] follow me. Matthew 19:21
And whosoever shall give to drink unto one of these little ones a cup of cold [water] only in the name of a disciple, verily I say unto you, he shall in no wise lose his reward. Matthew 10:42
Look to yourselves, that we lose not those things which we have wrought, but that we receive a full reward. 2 John 1:8
Is it possible for a man not to sin?
Not as long as he's alive in this world. But the promise of Christ is that He has paid for every sin of His children, even tomorrow's. (Hebrews 10)
His perfect obedience saves us; not our own.
"For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous." -- Romans 5:19