Why did he say that Hashem examines "Levav"?
'Rashi': You discern who was two hearts - one for good and one for evil.
Malbim: Even though the gold and silver that we gave is not ours, You do not look at the gold and silver, rather, at the heart. You should accept my donation for You know that I had no other intent!
What is "Meisharim"?
'Rashi': It is a good, straight heart. The same applies to "b'Yosher Levavi" later in this verse.
What did David say about Your nation that donated?
'Rashi': I know about my donation. I do not know about others, just what I saw that they donated amidst Simchah. I do not know if they gave willingly.
Radak, Malbim: I do not know their hearts, but I saw that they donated amidst Simchah. It seems that like me, they wanted to donate to You (Malbim - without other intents. You do not need the money, only the pure heart!)
What is the meaning of "ha'Nimtze'u Fo"?
'Rashi': This is like it says above (28:1) - David gathered all Sarei Yisrael... However, the rich of each city are not here, therefore the donation is not so great. Were the rest of Yisrael here, it would be greater! Radak - the prefix Hei is in place of Asher 1 , like "he'Halchu" (Yehoshua 10:24).
Radak (Yehoshua 10:24): Normally, the prefix Hei is not used with past tense to mean 'that'; this is an exception.
