Radak: One who does not guard the Mitzvos, he should be ashamed when he understands the Mitzvos that are written. If he steals, and sees written "do not steal", he will be ashamed!

Malbim: Most Mitzvos have a reason. However, if one rebels against Chukim, and accepts only matters that he knows their reason, he will be embarrassed if he looks at all the Mitzvos. Many of them, not everyone understands their true reason. He is ashamed if he finds Mitzvos whose reason he does not understand. However, after he accepts the Chukim whose reason is totally hidden, since he believes that Hashem knows their secret, all the more so he will guard the Mitzvos that are slightly understood, even if he does not grasp all their details.