1 Timothy 4:7-8 (NASB) says, "Discipline yourself for the purpose of godliness; for bodily discipline is only of little profit, but godliness is profitable for all things, since it holds promise for the present life and also for the life to come." I believe that if Paul thought that we were, even as FORGIVEN believers in Christ, going to continue to sin because that's how it is, then he would not waste his breath telling us to "discipline" ourselves "for the purpose of godliness".
Galatians 5:16-17 (NASB) says, "I say, walk by the Spirit, and you will not carry out the desire of the flesh. For the flesh sets it's desire against the Spirit, and the Spirit against the flesh; for these are in opposition to one another." Again, why would Paul tell us to do something that is impossible? The exhortation to "walk by the Spirit" seems pretty clear to me. Now, is it easy? No. Possible? YES!
When a person receives Christ into their heart, he/she becomes a "new creation" (2 Cor. 5:17). Our daily battles are "not with flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms" (Eph. 6:12), which means that we absolutely MUST not "conform any longer to the pattern of the world but be transformed by the renewing of your mind. Then you WILL be able to test and approve what God's will is - His good, pleasing and perfect will." (Romans 12:2)
Christ lived a perfect life. Believers in Christ are IN CHRIST. It IS possible for us to live as He did. God tells us to "be holy because I am holy" (I Peter 1:15). God is not going to tell us to do something that He will not enable us to do.
Before I go any further, I just want to make sure that I'm being clear. I'm not saying that once we are saved we are perfect. I'm saying (what I believe the BIBLE to say) that we don't have to sin any longer! According to Romans 6, we have been set free from the slavery of sin. Did you see that? We have been, it's ALREADY DONE! Now, it's our job to believe what God says about who WE ARE. We are saints of God. The word saint means, "most holy". Have you heard the quote, "I think, therefore I am"? Well, I am learning that to be exactly what happens. If we continue to tell ourselves and think that we are only "sinners saved by grace", then we will continue to sin. However, if we believe what God's word says, that we are "saints", then we will more likely live like it! Our spiritual walk solely depends on what our mind-set is. We are told over and over to "live in the Spirit", to "set our minds" on things above, etc. In Romans 8:4-6 we are told, "in order that the righteous requirements of the law might be fully met in us, who do not live according to the sinful nature but according to the Spirit. Those who live according to the sinful nature have their minds set on what that nature desires; but those who live in accordance with the Spirit have their minds set on what the Spirit desires. The mind of sinful man is death, but the mind controlled by the Spirit is life and peace". Did you notice how a person lives? We live according to how we have our minds set. It's a spiritual battle and it takes place in our minds. We CAN live a sinless life. My Savior did not die for me to live an almost sinless life! He lived so that I may live. So that I might have life more abundantly (John 10:10)!
Let me close with Ephesians 4:22-24:
"You were taught, with regard to your former way of life, to put off your old self, which is being corrupted by its deceitful desires; to be made new in the attitude of your minds; and to put on the new self, created to be like God in true righteousness and holiness."
YES! We CAN!