God is a trustworthy God. We can believe every word that comes from his mouth because it is impossible for him to lie (Hebrews 6:18). When Moses led the Israelites out of Egypt, the Israelites failed to believe the Lord and as a result they never entered the promise land (Joshua 5:6). God wanted them to enter the promise land, but their unbelief hindered them and this grieved the Lord.
The quickest way to grieve God is to not believe him. Unbelief is the only thing that can hinder the Lord from giving you the desires of your heart and the very things that He himself wants to give you.
Remember the story of Lazarus? Jesus wept (John 11:30) not because Lazarus had died (he’d known Lazarus was dead before he had arrive—it was the very reason he arrived!), but he wept because of Mary’s, Martha’s, and the others present unbelief. And since we know that Jesus only did what he saw his Father do (John 5:19), it’s safe to say that Jesus wept because his Father wept.
Believe God. The greatest gift we can give our God is our authentic Faith—to believe in Him and the One he sent (John 6:29).
A crisis situation drew out unbelief in the heart of the Israelites and they panicked and complained. A different crisis situation drew unbelief out of the heart of Mary and Martha and they blamed Jesus. It really doesn’t matter what the crisis or important situation is, if the response is anything other than faith we grieve God and but by the grace of God risk missing the very blessings we desire and that God himself wants to give us.
Remember, “God’s promise of entering his rest still stands, so we ought to tremble with fear that some of you might fail to experience it.” ( Hebrews 4:1)