Yes... there is a difference between blessings through the works of the law vs blessings through grace and faith. Certainly, in our understanding, we must first become part of the body of Christ through the born-again experience.
I wouldn't say that the congregation of Israel never walked in the spirit of faith but rather sometimes they did and sometimes they didn't. When Joshua entered into the promised land, it was indeed by faith. As a matter of fact, Hebrews 11 has a list of many who walked by faith (the Faith Hall of Fame chapter).
Building the house with God is in the TaNaKh which we call the Old Testament. Faith and grace is also in the TaNaKh (The Apostles actually preached it from those same scriptures). But, as you said, we no longer access it all by works but by obedience in faith.
So, in my view, whether in the TaNaKh or the New Testament, you still need God to build your house. The born-again experience certainly makes it a lot easier because the Holy Spirit now lives in us and guides us to blessings.
A few more thoughts!
Does being born again make it easier, or is it a necessary requirement for entry into the kingdom of God? I'm inclined to think the latter is the truth. (John 3:5)
As l understand the Hebrew scriptures, Abraham was a man of faith, and we are to follow in faith according to his covenant with God. The covenant made with Moses, a covenant of law, was not based on faith but on (re)action, and was necessary because of disobedience. Under Moses, the prophet delivered God's laws, and the people were required to follow the law to the letter...all the laws. The law didn't require a man to show faith, but to obey. If you obeyed, you received the blessings promised by God, and if you disobeyed you suffered the curses of disobedience.
Therefore, the only way for Israel to be saved (living in safety and peace in their land) was for the whole congregation to please God by corporately fulfilling the law in outward action.
I know that Hebrews 11 points us to the great men of faith, such as Moses and Joshua, but these men of faith proved to be the exception in lsrael, not the norm. Were they not the ones who heard the voice of God and told the masses how to act? The typical Israelite did not hear God's voice, but he did know the difference between a blessing and a curse. So, his behaviour was manipulated by pain and pleasure, the 'carrot and stick'. Acting out of obligation is what this kind of religion entails.
The Holy Spirit allows us, l believe, to know the Lord in the Spirit of love, creating a relationship that is better than the one that is founded solely on law and justice. The fear of the Lord is, l believe, just the 'beginning of wisdom'.