This can be reworded so that the abstract nouns "knowledge" and "insight" can be expressed as the verbs "learn" and "understand." Alternate translation: "God gave them the ability to learn and understand clearly" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
Here "all" is a generalization to show that they had a very good education and understanding. Alternate translation: "in many things that the Babylonians had written and studied" (See: [[rc://en/ta/man/translate/figs-hyperbole]])