And the kinsman said, I cannot redeem it for myself
On such a condition, because he had a wife, as the Targum suggests; and to take another would, as that intimates, tend to introduce contention into his family, and make him uncomfortable; so Josephus says F8, he had a wife and children, for that reason it was not convenient for him to take the purchase on such a condition:
lest I mar my own inheritance;
he considered, that as he had a wife and children already and as he might have more by marrying Ruth, his family expenses would be increased, and his estate diminished; and what would remain must be divided among many, and this estate in particular go to Ruth's firstborn, whereby his own inheritance would be scattered and crumbled, and come to little or nothing; add to all which, he might suppose that her ancient mother Naomi would be upon his hands to maintain also:
redeem thou my right for thyself
which I am ready to give up to thee, for thou hast no wife, as the Targum expresses it:
for I can not redeem it;
in the circumstances I am, and upon the condition annexed to the purchase.
F8 Antiqu. l. 5. c. 9. sect. 4.