What shield of Hashem's salvation did he get?
Radak: In all wars Your salvation was a shield for me. I was not stricken in one of all the wars!
Malbim (35-36): The second way that Hashem saves Tzadikim is that it seems that they win through their strength, but really, it is from Hashem alone, like the victory over Sancheriv. 1 In war, one needs a shield for protection. You give Your shield to me, as if I held it at the time of war, even though Your salvation held the shield, and not me. It says "Your hand sustains me", as if my hand won with Your help.
How did it seem that human strength defeated Sancheriv? There was no battle. An angel killed his entire camp (Melachim II, 2:19)! (PF)
What is the meaning of "va'Anvascha Tarbeni"?
Rashi: Your Midah of humility aggrandized me. Malbim - i.e. You do not want to attribute the victory that You won, so You aggrandize me and attribute it to me.
Targum Yonasan: With Your word You aggrandized me. Radak (Shmuel II, 22:36) - va'Anoscha is like "v'Anisa v'Amarta" (Devarim 26:5).
Radak #1: Your humility made me a great nation. Even though I was a small nation and my enemies were a great nation, I won, for Your humility was with me; it is as if I was a greater nation.
Radak #2: It is a metaphor - it is as if You lowered Your honor to watch over me.
Radak (Shmuel II, 22:36): It refers to Your help and desire - "veha'Kesef Ya'aneh Es ha'Kol" (Koheles 10:19).
