Psalm 78:22, "because they didn’t believe in God, and didn’t trust in his salvation," is part of a larger lament over the repeated rebellions of the Israelites in the wilderness after being delivered from slavery in Egypt. Let's break down the verse and its context:

"because they didn’t believe in God": This refers to a lack of faith in God's power, promises, and character. Despite witnessing incredible miracles like the plagues in Egypt and the parting of the Red Sea, the Israelites repeatedly doubted God's ability and willingness to provide for them. Their actions showed a lack of genuine trust and reliance on God.

"and didn’t trust in his salvation": This is closely linked to the first part. "Salvation" here refers to God's deliverance from Egypt, but it also has broader implications. It means not trusting in God's ability to protect, provide, and guide them. They didn't trust that God's plan for them was good and would ultimately lead to their well-being.

In essence, the verse highlights the Israelites' fundamental problem: a lack of faith and trust in God's power and promises. They saw God's mighty acts, yet they constantly doubted him and his ability to save them from their current difficulties.

Here's what this means in context:

Ungratefulness: Despite God's extraordinary acts of deliverance and provision, the Israelites were ungrateful and quickly forgot his goodness.
Rebellion: Their lack of faith led to rebellion against God's commands and a desire to return to their old lives.
Consequences: Their unbelief resulted in consequences like wandering in the wilderness for 40 years and not entering the Promised Land.

Key Takeaways:

The verse underscores the importance of faith and trust in God.
It serves as a warning against forgetting God's past faithfulness and doubting his ability to work in the present.
It suggests that a lack of trust can lead to rebellion and missed blessings.