1)
Why did David compose this Mizmor?
1.
Radak: It was when he fled Sha'ul, and people in Yisrael slandered him to Sha'ul [Malbim - and sought pretexts to kill him].
2.
Radak (31, from Shocher Tov): It is about Keneses Yisrael.
2)
Why did he say "Elokei Sehilasi"?
1.
Radak: My praise is in You - unlike those who boast about their evil.
2.
Malbim: You cause my praise - therefore, do not be silent.
3)
To what should Hashem not be silent?
1.
Rashi: To [the needs of] Yisrael.
2.
Radak: To what Resha'im do to me.
3.
Malbim: From waging my battle.
