This is an interesting passage in Isaiah:
Who among you fears the LORD
and obeys the voice of his servant,
who walks in darkness
and has no light,
yet trusts in the name of the LORD
and relies upon his God?
But all of you are kindlers of fire,
lighters of firebrands.
Walk in the flame of your fire,
and walk among the brands that you have kindled!
This is what you shall have from my hand:
you shall lie down in torment (Isa 50.10-11).
Here the prophet calls upon a people who are in a difficult and ambiguous situation. These may even understate the gravity of what they were undergoing; he says that they are walking about in the darkness and have no light. His audience, of course, was Judah in exile in Babylon. They were taken away from their home and led hundreds of miles away from the holy city, away from the temple of the LORD, to live among ungodly gentile heathens. They thought that the LORD had abandoned them, but here appears the Isaian prophet with a message that Jerusalem has served her term, that her penalty is paid (40.2), and that Israel will be gathered together once more in their homeland (43.1-6).
It is not unbelievable that some persons would have a hard time accepting this message. They saw women eat their offspring, the children they have borne and priest and prophet . . . killed in the sanctuary of the Lord (Lam 2.20). It is hard to accept that YHWH could still have much to do with Israel after that! It has been seventy long years since they have been in exile! This so-called prophet may be nothing more than a trouble-maker, looking to get the people into trouble with the Babylonians.
This is a pretty plausible judgment, and surely many of us would think along the same lines if we were in their position. How many people give up their faith and trust in God after suffering calamity and hardship? How many people want nothing more to do with God, when they undergo the gravest evils and misfortunes a person can imagine? To them it seems obvious that either God does not exist at all, or else that he doesn't care much for their welfare and safety.
But God is not like us, as I have been emphasizing in numerous recent posts, and he doesn't think or judge like we do. He insists that we trust in his judgment and that we don't try to walk by our own lights. The prophet confronted many people who did not trust the word of the LORD, nor did they accept God's evaluation and judgment of things, but instead insisted on evaluating things as they thought obvious. God's only word for them is: walk by your own lights! You will see that your plans will fall apart, your judgment was false, and your end will be an unhappy one; indeed, your plan will cross paths with mine and it will only go badly for you.
This is certainly what the Sadducees and the temple authorities were doing when they persecuted the Christians. Gamaliel told them: keep away from these men and let them alone; because if this plan or this undertaking is of human origin, it will fail; but if it is of God, you will not be able to overthrow them—in that case you may even be found fighting against God! (Acts 5.38-9) They did not heed his word, however, and found themselves wiped out and killed by the Romans, whereas Christians remained and now are more numerous than the Jews themselves. They were opposing God's plan even as they were going by their own lights, judging things as seemed obvious to them.
Of course, none of this is to say that our judgment is always faulty, or that we do not ever see things aright. The Bible does not ascribe utter ignorance to humanity, but it does teach us that at times, we are poorly mistaken and in a bad place. What seems obviously true to us may not be what God knows. In such cases, the call upon us is to trust God and his goodness. We have a fine ground for doing so: the goodness he has demonstrated to us in Jesus Christ. Knowing that God is good and that his intentions for all are good, therefore, we can walk by his commandments and obey the word of his servant.