Psalm 18:13 paints a picture of Yahweh (God) manifesting his power and judgment, likely in response to the distress or pleas of the psalmist. Let's break down the meaning:

"Yahweh also thundered in the sky": Thunder is often associated with God's voice or power. It signifies his presence and ability to command the forces of nature. In ancient Near Eastern cultures, thunder was frequently understood as a divine declaration.

"The Most High uttered his voice": This reinforces the idea of God speaking or making his presence known. "The Most High" is a title emphasizing God's supreme authority and position above all others.

"hailstones and coals of fire": These are destructive forces of nature that can cause widespread damage and destruction. They are interpreted as instruments of God's judgment or divine intervention. Hailstorms can ruin crops and cause physical harm, while coals of fire evoke images of burning and punishment. The vivid imagery highlights God's immense power and the potential consequences of opposing him.

Symbolic Interpretation:

While literal interpretations are possible, scholars often view these elements symbolically:

Judgment and Punishment: The hailstones and coals of fire can symbolize God's judgment against wickedness or enemies of the psalmist.
Divine Power and Authority: The verse emphasizes God's ability to control the natural world and use it to accomplish his purposes.
Answer to Prayer: It is often interpreted that God is actively responding to the psalmist's distress, demonstrating his faithfulness and willingness to intervene on behalf of those who trust in him.

In the context of the entire Psalm 18, which is a song of deliverance, this verse illustrates how God intervened powerfully to rescue the psalmist from his enemies. It's a display of divine might and a reassurance of God's protection for those who seek refuge in him.