Leviticus 23.29
Septuagint


pasa yuch, htiV
mh tapeinwqhsetai en auth th hmera tauth, 
exoloqreuqhsetai ek tou laou authV

New Testament - Acts 3.23

estai de 
pasa yuch htiV 
ean mh akoush tou profhtou ekeinou
exoleqreuqhsetai ek tou laou 

Septuagint

Every soul that shall not be humbled in that day, shall be cut off from among its people
 

New Testament

And it shall be, that every soul that shall not hearken to that prophet, shall be utterly destroyed from among the people

Masoretic Text

For whatsoever soul it be that shall not be afflicted in that same day; he shall be cut off from the people 

Comments:  The NT differs from both the LXX and the MT in mentioning a prophet.  The prophet seems to be supplied from Deuteronomy 18.19.  As an integration of the two verses, Acts 3.23 seems to derive from known Old Testament sources.

The inserted phrase is very similar to Deuteronomy 13.3 (LXX):  “you shall not hearken to the words of that prophet” - ouk akousesqe twn logwn tou profhtou ekeinou.