"I will cry out to the Lord, I will cry out to the Lord for mercy. Why twice 'my voice'? Similarly, the verse says (Psalms 86:3) 'Have mercy on me, O Lord, for I call to You all day long.' Twice.
Rather, this is what David said: 'Have mercy on me that I may not fall into his hand, and have mercy on me that he may not fall into my hand.' And so, 'my voice to the Lord I cry out' means that I may not fall into His hand, and 'I plead to the Lord with my voice' means that he may not fall into my hand." [The passage is discussing the repetition of certain phrases in Psalms and why they appear twice.
Specifically, it focuses on the phrase "my voice" which appears twice in the opening line of Psalm 130: "Out of the depths I cry to you, Lord; Lord, hear my voice." The commentary explains that the repetition of "my voice" is meant to convey two different intentions: the first "my voice" is a plea to God to not let the speaker fall into His hand, and the second "my voice" is a plea to God to not let the speaker's enemies fall into his hand.
This interpretation is based on a similar repetition of the phrase "have mercy on me" in Psalm 86:3, and the commentary explains that David himself made this distinction when he used the phrase "have mercy on me" twice in one verse.]