Despite seeing the great miracle of God’s deliverance through the Red Sea, Israel soon fell into grumbling against the Lord when they ran out of fresh water (Ex. 14:1–15:24). As we have seen, the Israelites’ grumbling was not a mere recognition of their lack of a basic necessity and a crying out to the Lord in faithful lament over it; rather, their grumbling was a faithless response that found fault in our Creator for where His providence had brought them. God graciously provided for them by making the bitter water at Marah potable, and He told them that their faith, displayed in their obedience to Him, would keep Him from sending upon them the same plagues He had sent on Egypt (Ex. 14:25–27). Note, however, the implicit warning here—Israel’s lack of faith, as seen in their disobedience, would result in their suffering the same kinds of judgment that the Egyptians did.
Given what we know about Israel’s later experience in the wilderness, the grumbling at Marah served as a portent of what lay ahead. Israel would repeatedly show a lack of faith and grumble against God (e.g., Ex. 17:3; Num. 14:2; 16:41). In fact, not long after the incident at Marah, the Israelites grumbled again, as we see in Exodus 16:1–8. Instead of trusting that the God who had saved them from slavery would also meet their basic needs of sustenance, the Israelites grumbled when they found themselves out of food (Ex. 16:1–3).
Israel’s lack of bread and meat led the people to wish they had died in Egypt, where at least they would have had enough food before they died (Ex. 16:3). We have no evidence that the Israelites ever went hungry while they were slaves, but they doubtless exaggerated how “good” they had it in Egypt compared to the wilderness. In any case, all of us can falsely believe that days gone by were better than they actually were and that our present difficulties are worse than they are. Matthew Henry comments, “Discontent magnifies what is past, and vilifies what is present, without regard to truth or reason.”
God answered the Israelites’ grumbling by promising to send them food daily and by revealing that their complaining was really against Him, not Moses and Aaron. But this provision would come with a test that would determine whether they actually trusted the Lord. With the exception of the sixth day of the week, they would have to gather only what they needed for a day (Ex. 16:4–8). To gather more would prove that they did not believe that God would continue to provide.