Can you tap energy before playing Divine Judgment and retain the excess energy after Divine Judgment discards down to 2?

Ruling: Yes, you can tap energy before playing Divine Judgment and retain the tapped energy even after Divine Judgment discards your untapped energy down to 2.

Sequence:

• Tap the desired amount of energy (e.g., all 10)
• Play Divine Judgment
• Divine Judgment discards untapped energy down to 2
• Previously tapped energy remains available to spend