Psalms 6:1

on the sheminith A harp of eight strings, known as sheminith, and so we find (in I Chron. 15: 21): “So-and-so and his sons on the sheminith to conduct.”

For the Chief Musician, with Neginoth, on the Sheminith. A Psalm of David. – Already we have explained the sense of Neginoth and Sheminith and the other kinds of musical instruments in the Psalm Answer me when I call (Ps. iv.). There are some (Targum ad loc.) who interpret Sheminith as a lyre which had eight strings, and the Psalm as being recited to the accompaniment of this music. The Haggadic interpretation (Babli, Menahoth 43b) (applies it) to circumcision, which was performed on the eighth day, but this is far-fetched. This Psalm possibly was uttered by David with reference to his sickness; it is also possible likewise that it was uttered in the language of anyone crushed by sickness, for David composed many of the Psalms which combine prayer and supplication that they might be suitable for any suppliant; and such, I think, is the case in this Psalm. And some say (Ibn Ezra ad loc.) that it was uttered with reference to the Exile, for Israel in exile was like those who are sick and crushed.