He speaks of their formalism and false piety. He uncovers the heart attitude that accompanies their physical fasting. He calls them on the carpet for their congregational strife and calls them to repent of their false profession. That loud cry brings us to verse 6. IF they will heed Isaiah's warning THEN there are some wonderful promises awaiting them.
These folks have faced serious affliction, and rightfully so. Their sins have brought them a great deal of suffering. God has seemed absent. The light of His countenance has been withdrawn. But, IF they will return to the God of mercy THEN He will receive them as the prodigal son's father did.
Here are God's "THEN" promises to them:
2) "The glory of the LORD will be your rear guard." - There is a security found in turning to Christ. The righteous are safe on all sides. The LORD is their defense and if He is for us who can be against us?!
3) "Then you will call and the LORD will answer, you will cry, and He will say 'Here I am'." - While in their rebellion God's ear was turned from them - sin affects our prayers. Now that they have turned from their sin back to their God, His ear will be fine tuned to them. He will hear and He will answer His people.
Sin separates, repentance unites. Sin makes us selfish, repentance makes us servants. The change that it brings is described in verse 10. Those who had been takers will become givers. They will give themselves to the hungry, and satisfy the desire of the afflicted. And, as they give so shall they receive. God will continually guide you, and satisfy your desire in scorched places, and give strength to your bones; and you will be like a watered garden, and like a spring of water whose waters do not fail."
"While we are here, in the wilderness of this world, we have need of continual direction from heaven" (Henry). God will grant that to His servants. He promises to guide us, to satisfy our true needs, to strengthen us in our weakness, and to make us like a never failing spring.
Quoting Henry once more, "As a spring of water, though it is continually sending forth its streams, is yet always full, so the charitable man abound sin good as he abounds in doing good, and is never the poorer for his liberality." The Christian life is an amazing circle. God gives to us that we may give for Him. As we give for Him, He continues to supply us with more that we might continue to give more. Therefore, give that it might be given to you, good measure, pressed down, and running over!
I suppose the question is, are we the folks of verses 2-7? Are we takers? Are we religious formalists? Are we self seeing hypocrites? If so, we need know that our "then" will not be a pleasant one. But if we are the folks of verses 8-11, if we are givers because He has first given to us, "then" we have precious and imperishable promises. Who are we living for ourselves or our Maker? What "if" are we? What "then" shall we receive?