Ruth 4:6: The Kinsman-Redeemer's Refusal to Redeem
Verse 6:[1] (Ruth 3:12, 13) And the kinsman said, I cannot redeem it for myself, lest I mar mine own inheritance: redeem thou my right to thyself; for I cannot redeem it.

[I yield my right, etc.] Hebrew: I am not able to claim, or to redeem, for myself[2] (Syriac, Junius and Tremellius, Pagnine, Montanus). That is, It is not pleasing to me: For he was able by right (Piscator).
[For I must not destroy the posterity of my family, פֶּן־אַשְׁחִ֖ית אֶת־נַחֲלָתִ֑י] Lest perchance I spoil, or ruin, my inheritance, or possession (Montanus, Junius and Tremellius, Piscator, Vatablus, Drusius, Grotius). Question: How would he have done this? Responses: 1. By transferring his possession unto his son, whom perchance he might beget as an only child, and who would succeed into the name of the deceased husband: so that it might happen that his own name might perish with his own death (Piscator, similarly Junius). It was the same reason as that of Onan, Genesis 38:9 (Junius). 2. Others maintain that this man had a wife and children. Thus Josephus, who thus, I think, understood it: I am unwilling add another wife, and to bring other children into the house, lest I disturb the peace of my family, and, being intent upon the affairs of another, neglect my own (Grotius). I have both a wife and many sons, who will well enough look after my possessions and name: besides, if from the young woman Ruth many sons should be added (for besides the firstborn, to be put in the place of the kinsman, all the rest shall be reckoned my sons and heirs with a right equal to those prior), my possessions would then be overly dismembered and dispersed, and perhaps involved in disputes (Tirinus out of Serarius, similarly Lapide). That he had a wife, the Chaldean testifies in this place. Moreover, it appears that he had that in Leviticus 18:18 in mind (Drusius).
Lest I mar mine own inheritance; either, first, Because having no children of his own, he might have one, and but one, son by Ruth, who, though he should carry away his inheritance, yet should not bear his name, but the name of Ruth’s husband; and so by preserving another man’s name, he should lose his own. Or, secondly, Because as his inheritance would be but very little increased by this marriage, so it might be much diminished by being divided amongst his many children, which he possibly had already, and might probably have more by Ruth. Redeem thou my right, which I freely renounce and resign to thee.
[1] Hebrew: וַיֹּ֣אמֶר הַגֹּאֵ֗ל לֹ֤א אוּכַל֙ לִגְאוֹל־לִ֔י פֶּן־אַשְׁחִ֖ית אֶת־נַחֲלָתִ֑י גְּאַל־לְךָ֤ אַתָּה֙ אֶת־גְּאֻלָּתִ֔י כִּ֥י לֹא־אוּכַ֖ל לִגְאֹֽל׃
[2] Hebrew: לֹ֤א אוּכַל֙ לִגְאוֹל־לִ֔י.