Commenting on 2 Samuel 6:21, Daniel E. Fleming noted that:
The Masoretic Text (MT) and Greek
Codex Vaticanus (LXXB) present vastly different texts, and “the
people of Yahweh” are only in the MT:
MT: Before Yahweh who chose me
over [lit. ‘more than’, mē] your father and over all his house to
command me chief [nāgîd] over [‘al] the people of Yahweh, over
Israel, and I will perform [śḥq] before Yahweh.
LXXB: Before the Lord
[=Yahweh] I will dance. Blessed be the Lord [=Yahweh], who chose me over your
father and over all his house to appoint me leader for his people, for Israel.
And I will perform [παιξομαι, for Hebrew śḥq]
and the dance before the Lord [=Yahweh] (Daniel E. Fleming, Yahweh Before
Israel: Glimpses of History in a Divine Name [Cambridge: Cambridge
University Press, 2021], 194-95)