“to go out and to come in.” The phrase “to go out and to come in” is an idiom and the figure of speech polarmerismos. The figure polarmerismos occurs when two opposite things are juxtaposed such that they refer to a complete whole. For example, the “long and short” of an argument is a way of referring to and summarizing the whole argument, and “to go out and come in” refers to all the daily activities of life. A person gets up in the morning and goes out to do daily work, then comes in at night, so the phrase is an idiomatic way of referring to the totality of living life.
The translation in NICOT catches the sense: “I have the same vigor now as I had then for warfare and for daily duties.”a Solomon used the same basic idiom when he was telling God that he did not know how to live as a king: “I do not know how to go out or come in” (1 Kings 3:7). The figure polarmerismos is used a number of times in the Bible, both in the Old Testament and the New Testament (e.g., Deut. 11:19; 28:19; 31:2; Josh. 14:11; 2 Sam. 3:25; 1 Kings 4:20; 2 Kings 11:8; Lam. 3:63; John 10:9; Acts 9:28).