So God was with the lad; and he grew and dwelt in the wilderness, and became an archer. (Gen 21,20)
It is not easy for us to understand that God often blesses things that are not of His will. Even things that He would not approve of. I don't mean ones that are directed against Him, or that are straight out of hell in nature. But He will bless many decisions, actions, activities that He did not initiate, did not intend, simply because they were carried out by His own people on earth.
Scripture tells us that "God was with the boy." What does that mean? Nothing more and nothing less than that God's hand protected him to grow up. Back then a human life hung by a thread, and the circumstances in which its thread might be broken by sickness or violence were many more than today. Ishmael was not a worshiper of God and a bearer of His blessings on earth in the sense that Isaac later was. We do not know if he believed in the God of Abraham (and did not abandon faith in Him after he was cast out by Abraham). If he did, we have no idea if and how his faith manifested itself. So we know that "God was with the boy", but we no longer know whether "the boy was with God". Rather, we can believe that Ishmael's faith merged with the religion of the surrounding tribes, resulting in yet another of the many mixtures of true faith and pagan superstition that have filled the earth from time immemorial.
To be blessed like Ishmael is certainly good. But it is a blessing that ends with its recipient, does him good, but is not enough to continue to bless the earth through him. Ishmael was not thinking of anything like this, and his restless nature certainly wasn't up to it. He had become a hunter, the head of the tribe, and the people around certainly had respect of him, perhaps even fear. But we can't really imagine him being a light to others in their quest for God, as Abraham was. How often we are concerned only with God blessing us, simply to make us well. Yes, it's good when that happens. It's a time to enjoy, to rejoice. But if we don't want to stop here and want to move on, we need to get from Ishmael to Isaac in our thinking. To not just want to be comfortable (albeit with God), but to seek which thing is sovereignly God's so that we can enter into it and become a blessing to this earth.
This river of blessing flows from a source we do not possess. So the only way to take from its fullness and give forth is to enter into it.