So Moses brought Israel from the Red sea, and they went out into the wilderness of Shur; and they went three days in the wilderness, and found no water. And when they came to Marah, they could not drink of the waters of Marah, for they were bitter: therefore the name of it was called Marah. And the people murmured against Moses, saying, What shall we drink? Exodus 15:22-24

So now the first test for the Israelites as they are now free in the Wilderness. Even though God delivered the Israelites from slavery, they were never happy. They have this unrealistic expectation that life would be easy because they were delivered. We as Christians have the same issues, we believe that life should be easy because Jesus delivered us. 

After everything Moses did for the Israelites, they turned on Moses already. Complaining about him, blaming him for everything that goes wrong. This is the same thing we do with Christ. When things dont go our way, we blame Christ, when we dont get what we want, we blame Christ. 

And he cried unto the LORD; and the LORD shewed him a tree, which when he had cast into the waters, the waters were made sweet: there he made for them a statute and an ordinance, and there he proved them,  Exodus 15:25

Notice what Moses solution was to the problem, he cried out to God. And guess what God gave Moses the solution. Instead of complaining and grumbling to God, why not give Him praise and ask him for direction? God will always provide!

And said, If thou wilt diligently hearken to the voice of the LORD thy God, and wilt do that which is right in his sight, and wilt give ear to his commandments, and keep all his statutes, I will put none of these diseases upon thee, which I have brought upon the Egyptians: for I am the LORD that healeth thee. Exodus 15:26

Heres an amazing blessing God put on the Israelites, if they will listen to God and follow his ways, he well keep them from diseases and heal them! Imagine that, if you just listen to God and be obedient He will take care of you! Just like the Israelites, we need to learn to be obedient to God and trust Him

And they came to Elim, where were twelve wells of water, and threescore and ten palm trees: and they encamped there by the waters.  Exodus 15:27

God is providing all the needs for the Israelites , even though they were weak and helpless in the Wilderness, He provided for them, He empowered them, He delivered them from all their afflictions.

The Water of Marah was bitter and undrinkable, but God made it sweet and sustaining for their lives, just as we need the Living Water of Jesus Christ Amen!