It is under this condition only, O Karna, that you will give your ear-rings to Shakra. Then you will be able to destroy your enemies in battle.
इत्येव नियमेन त्वं दद्याः शक्राय कुण्डले। तया त्वं कर्ण संग्रामे हनिष्यसि रणे रिपून्।॥