Questions: What significant decision did King David make during his reign?

The answer is: He established Jerusalem as the capital of Israel.

Explanation for each option:

1. He presented the Ten Commandments.
   This is incorrect. The Ten Commandments were presented by Moses, not King David. Moses received the Ten Commandments on Mount Sinai, according to the biblical narrative.

2. He established Jerusalem as the capital of Israel.
   This is correct. King David is credited with establishing Jerusalem as the political and spiritual capital of Israel. He conquered the city and made it the center of his kingdom, which was a significant decision in unifying the nation and establishing a central place of worship.

3. He led the Jews out of Egypt.
   This is incorrect. The exodus of the Jews from Egypt was led by Moses, not King David. This event occurred long before David's reign.

4. He united the twelve tribes of Israel.
   While this is partially correct, as David did play a role in uniting the tribes, the more specific and significant decision during his reign was establishing Jerusalem as the capital. The unification of the tribes was a process that began with Saul and was solidified under David's leadership.