However just as new babies that come into the world, we are brand new babies spiritually. Maturity and growth comes with time, and choosing to allow the word of God to correct us, and develop us in our walk with God.
The grace and love of God cannot be an excuse to continue in sin; once we have been shown by his word that a certain thing we are doing is wrong. Just as we expect our children to listen to us, and obey us because we have their best interest at heart; and the principle is the same with God's desire for us to obey His word. It's for our best, because He loves us.
When we will fully continue to sin, and disobey Him, we close the door to receiving the many blessings He wants to give u, and promises us in scripture. When Jesus came, he did not tell the disciples to cast away the commandments, He emphasized His deity by telling them "If you love me you will keep my commandments."
John 14:15 If ye love me, keep my commandments.
And then in ch. 15-he states:
John 15:10 If ye keep my commandments, ye shall abide in my love; even as I have kept my Father's commandments, and abide in his love.
Then in the next verse he declares:
Joh 15:11 These things have I spoken unto you, that my joy might remain in you, and that your joy might be full.
Again he tells us the value of obedience; He desires our best. He wants us to walk in wholeness, health, prosper in all we do. But as Paul tells us:
Rom 6:23 For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.
We are always left with the freedom to make our own choices, but also to live out the consequences of them.
It grieves my heart to watch many times, when a person chooses to go their own willful way; it always leads to pain an destruction.
Yes, there can be a form of legalism in religion. But, if we have a heart to obey because we love the Lord, this very well may be misunderstood by many. God knows the heart, and knows the issues of it.