Malbim: Straightness says so. It is planted in every person's nature, to love straightness and Tzedek. A Rasha who veers from this, he opposes his Nefesh's nature. His Nefesh afflicts him and pressures him to return to the good. Therefore, Resha'im are full of regret
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Based on Radak's previous words (refer to 75:5:2:2), it seems that this refers to worldly pleasures. (PF)
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What is the meaning of "Al Tarimu Keren"?
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Radak: Do not raise your heads against Hashem, like you do, that you do not fear Him or humble yourselves in front of Him. He, and not Your power, benefits You!