Psalm 78 is a recounting of Israel's history, highlighting God's faithfulness and Israel's repeated rebellion despite His blessings. Verse 17, "Yet they still went on to sin against him, to rebel against the Most High in the desert," is a stark statement about Israel's persistent disobedience during their wilderness wanderings after the Exodus from Egypt.

Let's break it down:

"Yet they still went on to sin against him..." This indicates a continuation of sinful behavior. It's not a one-time lapse but a pattern of repeated offenses against God.

"...to rebel against the Most High..." "Most High" is a title for God that emphasizes His supreme power, authority, and sovereignty. To rebel against the "Most High" is to defy the ultimate authority, demonstrating a deep lack of respect and trust.

"...in the desert." The location is significant. The desert was a place where God provided for Israel in miraculous ways: manna from heaven, water from a rock, protection from enemies. Despite witnessing these displays of God's power and provision, and being completely dependent on Him for their survival, they still chose to rebel. This underscores the depth of their ingratitude and the perversity of their will.

In essence, this verse highlights the following:

Israel's persistent sinfulness: They were prone to turning away from God.
The seriousness of their rebellion: It was a direct defiance of God's supreme authority.
The context of their sin: They rebelled despite God's provision and protection, making their actions even more egregious.
A pattern of ingratitude: They were unthankful and distrustful despite witnessing God's miracles.

This verse serves as a cautionary tale, reminding readers of the human tendency to turn away from God even when He is actively working in our lives. It also underscores the need for humility, gratitude, and a steadfast commitment to obedience.