What does Isaiah 1:4 mean?
God is bringing a kind of lawsuit against His people Israel for breaking their covenant with Him (Isaiah 1:1–3). This verse reveals that God is more than just angry. His heart is broken over the sins of Israel. The word "ah" is an expression of hurt and sadness at this "sinful nation."The Lord's case introduces the core of Israel's heart problem as being about sin: failing to do what's right. The people are heavy with iniquity: a word for sin that means "twisted-ness.". Each new generation is the offspring of "evildoers:" rebels who deny God's authority. Like their parents, they deal corruptly, meaning that their relationships are defined by dishonesty to favor themselves over others. Sin, disobeying the Lord, serving self, saturates everything the people do.
Though God is focused on Israel here, they are not alone in this sinful state of being. In the New Testament, Paul will express the universal truth that all have sinned and fall short of God's glory (Romans 3:23). Isaiah's book will point to the Savior to come who will make forgiveness and freedom from sin possible by bearing that sin for us (Isaiah 53:12).
The result of sin in Israel is this, the Lord says: They have forsaken Him. His people are doing everything they can to leave Him behind, to live apart from Him. In committing to their sin, they demonstrate that they despise the Lord. Isaiah will use this name for Yahweh, "the Holy One of Israel," more than twenty times in his book.
The Lord says that the people of Israel have become utterly estranged from Him in their hearts.