Please share your understand of "the handwriting of ordinance that was against us" but allow me to share mine first:
The law is either a blessing or curse depending whether the Israelites obey or disobey cf Deuteronomy 28.
He repeated in Deuteronomy 30:11-20 Now what I am commanding you today is not too difficult for you or beyond your reach. It is not up in heaven, so that you have to ask, “Who will ascend into heaven to get it and proclaim it to us so we may obey it?” Nor is it beyond the sea, so that you have to ask, “Who will cross the sea to get it and proclaim it to us so we may obey it?” No, the word is very near you; it is in your mouth and in your heart so you may obey it. See, I set before you today life and prosperity, death and destruction. For I command you today to love the Lord your God, to walk in obedience to him, and to keep his commands, decrees and laws; then you will live and increase, and the Lord your God will bless you in the land you are entering to possess. But if your heart turns away and you are not obedient, and if you are drawn away to bow down to other gods and worship them, I declare to you this day that you will certainly be destroyed. You will not live long in the land you are crossing the Jordan to enter and possess. This day I call the heavens and the earth as witnesses against you that I have set before you life and death, blessings and curses. Now choose life, so that you and your children may live and that you may love the Lord your God, listen to his voice, and hold fast to him. For the Lord is your life, and he will give you many years in the land he swore to give to your fathers, Abraham, Isaac and Jacob.
There is nothing against the people of God if they choose wisely i.e. to obey His Word.
Now come back to the verse "...nailed the handwriting of ordinances that was against us to the cross." Who are the "us"?
He died on the cross so that our sins are forgiven but the book of Hebrews said' "If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left." So what is obeying His commandments helping?
Paul said "What shall we say, then? Shall we go on sinning so that grace may increase?" Grace is not a license to sin.
Paul said "What shall we say, then? Is the law sinful? Certainly not! Nevertheless, I would not have known what sin was had it not been for the law." And he didn't mix the law with grace.
It's either every word coming from the mouth of God or it's all wrong.
The Word of God came to show man how one could live according to His Word. Man does not necessarily have to sin to live.
The Word of God came to show man how one could live a sinless life by the Spirit.
Why does man trust in his weakness and say one could not live by not sinning?