I will cut off thine arm, i.e. I will take away thy strength, which is oft signified by the arm, as Job 22:8 Psalms 37:17, or all that in which thou placest thy confidence and security; either,
1. The ark, which is called God's strength, Psalms 78:61, and was Eli's strength, who therefore was not able to beat the very tidings of the loss of it, 1 Samuel 4:18. Or,
2. His priestly dignity or employment, whence he had all his honour and substance. Or rather,
3. His children, to whom the words following here, and in the succeeding verses, seem to confine it, who are the strength of parents: see Genesis 49:3 Deuteronomy 21:17 Psalms 127:4,5. The arm of thy father's house, i.e. thy children's children, and all thy family; which was in great measure accomplished, 1 Samuel 22:16, &c. There shall not be an old man in thine house; they shall generally be cut off by an untimely death before they be old.