Joshua 4:10
9 Joshua also set up 12 stones in the middle of the Jordan in the very place where the priests carrying the ark of the covenant stood. They remain there to this very day. 10 Now the priests carrying the ark of the covenant were standing in the middle of the Jordan until everything the Lord had commanded Joshua to tell the people was accomplished, in accordance with all that Moses had commanded Joshua. The people went across quickly, 11 and when all the people had finished crossing, the ark of the Lord and the priests crossed as the people looked on.
LXX Joshua 4:10
9 And Joshua set also other twelve stones in Jordan itself, in the place that was under the feet of the priests that bore the ark of the covenant of the Lord; and there they are to this day. 10 And the priests that bore the ark of the covenant stood in Jordan, until Joshua had finished all that the Lord commanded him to report to the people; and the people hasted and passed over. 11 And it came to pass when all the people had passed over, that the ark of the covenant of the Lord passed over, and the stones before them.
Notes and References
"... According to the short formulation of [the Greek text], Joshua's actions closely followed the command of God, while the plus of [the Masoretic text], possibly deriving from verse 12, 11:15, or from Deuteronomy 3:28, stressed that the command was by Moses ..."
Tov, Emanuel Textual Criticism of the Hebrew Bible (pp. 328-329) Fortress Press, 2001