I cannot redeem it for myself - The Targum gives the proper sense of this passage: "And the kinsman said, On this ground I cannot redeem it, because I have a wife already; and I have no desire to take another, lest there should be contention in my house, and I should become a corrupter of my inheritance. Do thou redeem it, for thou hast no wife; for I cannot redeem it." This needs no comment. But still the gloss of the Targum has no foundation in the law of Moses. See the law, Deuteronomy 25:5-9.
I mar mine own inheritance - The meaning of these words is doubtful. Some explain them by saying that the גאל gā'al had a wife and children already, and would not introduce strife into his family. Others think that there was a risk (which he would not incur) of the go‘el‘s own name being blotted out from his inheritance Rth 4:10 . Others take the word translated as “mar” in a sense of wasting or spending. If he had to find the purchase-money, and support Naomi and Ruth, his own fortune would be broken down, if, as is likely, he was a man of slender means. Boaz, being “a mighty man of wealth,” could afford this.
Redeem thou my right - Literally, redeem my redemption - perform that act of redemption which properly belongs to me, but which I cannot perform.