1)
The one who reviled David - what did he say?
1.
Radak: "He has no salvation in Elokim" (3:3).
2.
Malbim: They say that You will remove kingship from me due to the sin of Bas Sheva.
2)
What was his trust in Hashem's word?
1.
Radak: He will fulfill it for me.
2.
Malbim: I answer that Your promise cannot depart, since it was initially via Chesed.