Hello daydreamer40, thanks for your post.
Consider what you are replying to and the scriptures in them. Where does it say in the post you are responding to that it is talking about obeying the letter of the law perfectly to become perfect?
This idea makes no consideration for growing in Grace and in the Knowledge of God's truth. God's Word teaches that when we first become Christians we are babes and need to grow in the knowledge of God's WORD in order to follow it by faith *1 PETER 2:2' 1 CORINTHIANS 3:1-2; MATTHEW 11:25; 2 PETER 3:18. Others call this process Sanctification which is the work of a lifetime. Something you thought may not be sin today as you grow in the KNOWLEDGE of God's WORD may be sin for you tommorrow.
There is no such thing that someone is instantly perfect although by faith as long as we are living up to all the knowledge of God's WORD that Gods has revealed to us we are perfect in God's eyes and are believers and followers of God's WORD.
The letter of the law is but the very beggining. Its purpose is to show us that without Christ we can do nothing but with him all things as we have faith in God's WORD. We are all sinners in need of a Saviour, yet the good news is that we have a Saviour to save us from our sins the more and more God reveals them to us day by day. As God reveals these things to us he expects us to take up our cross and follow him. Faith in God's WORD is how we receved him and it is be faith in God's WORD that we are to walk. This is what it means to walk in the Spirit. It is only by walking in the Spirit that we will not fulfill the lusts of the flesh.
The Good news of the gospel is that we have a Saviour that wants to save us from our sins not in sin. Those who continue in KNOWN UNREPENTANT sin will not enter God's KINGDOM because they have rejected the gift of God's dear son *HEBREWS 10:26-27; ROMANS 6:23.
Thanks for sharing. Hope this is helpful.
Will have to catch up latter guys late my time. Good discussion will chat more latter