What is the meaning of "Atah Tze'adai Tispor"?
Rashi: Now, You do evil to me. You count my steps.
Malbim: You wait in ambush on my steps, and seek to make me fall in a pit without reason.
How does Hashem not guard his sin?
Rashi: You wait for my sin in order to punish me. This is like "v'Aviv Shamar Es ha'Davar" - he waited until it would be fulfilled. 'Do not say, Shemor for me by idolatry Ploni' (Sanhedrin 63b), i.e. wait for me.
Ibn Ezra: It means, You guard only my sin. 'Rak' is omitted, like I explained "Ein Tov ba'Adam she'Yochal v'Shasah..." (Koheles 2:24; it means, Rak she'Yochal).
Malbim: You do not wait for me to sin. You punished me before I sinned. This is like one who hates his colleague, and waits in ambush to fell him with a pretext, without any sin. If so, how can I hope that You will to love me so much [to revive me, and return to me good in place of my afflictions]?!
