What does Isaiah 1:6 mean?
In this and the previous verse (Isaiah 1:5), the Lord seems to be describing the spiritual condition of Judah, Israel's southern kingdom. Failure to treat spiritual wounds will lead to physical destruction as described in the following verses (Isaiah 1:7–8).God has said Israel's head is sick and her heart is weak. The people do not understand: all the good they have and need comes from the Lord. So, they continue to rebel. They fight against the one who provides for them. They do not trust Yahweh, and so they grow weaker and weaker.
Now the Lord describes their growing weakness as systemic throughout the "body" of Israel, from the sole of the foot to the head. Nothing about them is spiritually healthy. Israel is covered in spiritual bruises, sores, and open wounds because of her rejection of God. Still, she refuses to treat her wounds (Jeremiah 8:22). That would mean draining boils, bandaging wounds, and applying medicine. Spiritually, it would mean rebuking sin and leading others to properly honor God. The picture is of a limping, bleeding, fainting patient that expects to go about her day as if nothing is wrong. She denies her need for healing and continues to do what causes her harm.
The result of that spiritual weakness will be physical destruction (Isaiah 1:7–8).