1)
What should Hashem hear and answer?
1.
Radak: David's request ("Shivti b'Veis Hashem").
2.
Malbim: Hashem should remove all hindrances and distractions from Avodas Hashem. His request is not for the sake of his needs, rather, so via this he can attain the primary goal - so he can serve Hashem. First he asks to be saved from his enemies.
