General Information:

David continues his song to Yahweh.

I can run over a barricade

Here "barricade" may refer to a group of soldiers or to a stone wall. Either way it means God enables David to defeat his enemies.

David is exaggerating to emphasize Yahweh's help. AT: "I can climb over the wall that surrounds their city" (See: rc://en/ta/man/translate/figs-hyperbole)

"Everything Yahweh says is true"

The metaphor "a shield" emphasizes God's power to protect his people. (See: rc://en/ta/man/translate/figs-metonymy)