Isaiah 1 How Does God See Us When We Are Disobedient

In our studies in the book of Leviticus, we have learned of God's sacrifices, feast days, and moral law and how important it is for one to "draw near" to God in all. So what happens when a person or nation is obedient in sacrifices, Sabbaths, and appointed times but negligent to keep the moral law of God? How does God view our offerings to him when we have left off to do what Y'shua/Jesus called the "weightier matters"  of the law? This and more in this verse by verse teaching of Isaiah chapter 1.