## He began to be ##

This Hebrew phrase means "He was the first to be." It can be translated here as "Nimrod was the first to be" or "Nimrod was the first."

## a mighty man ##

"a mighty warrior." It can be translated as "powerful soldier" or "powerful conqueror."

## before Yahweh ##

This can be translated as "in Yahweh's sight."

## The first centers ##

Possible meanings are 1) the first centers he developed or 2) the important cities.

## That is why it is said ##

This can be translated as "This is the reason people say." It introduces a proverb. Your language may introduce proverbs and sayings in a different way.