Jeremiah 31.15
Septuagint

fwnh en Rama hkousqh qrhnou, 
kai klauqmou, kai odurmou:
Raxhl apoklaiomenh 
ouk hqele pausasqai 
epi toiV uioiV authV
oti ouk eisin

New Testament - Matthew 2.18

fwnh en Rama hkousqh
klauqmoV kai odurmoV poluV:
Raxhl klaiousa ta tekna authV
kai ouk hqelen paraklhqhnai,

oti ouk eisin

Septuagint

A voice was heard in Rama, of lamentation, and of weeping, and wailing; Rachel would not cease weeping for her children, because they are not

New Testament

A voice was heard in Ramah,
Weeping and great mourning,
Rachel weeping for her children;
And she would not be comforted, because they are not

Masoretic Text

Thus saith Jehovah:  A voice is heard in Ramah, lamentation, and bitter weeping, Rachel weeping for her children; she refuseth to be comforted for her children, because they are not

Comments:  The NT and the MT agree.  The Brenton’s LXX text disagrees. 

The major conflict between the LXX and the MT is in one verb.  The LXX has “would not cease” where the NT gives “would not be comforted.”  This disagreement disappears in Codices Alexandrinus and Sinaiticus.  These both contain paraklhqhnaiin place of pausasqai, with the NT.

A less serious difference is mitigated by considering New Testament variants.  Many New Testament manuscripts replace “hkousqh klauqmoV” with “hkousqh qrhnoV kai klauqmoV.”  Thus, in these manuscripts - for instance, Codices C, D, L, W, 0123; the f13 miniscule family; and the Majority text - Matthew also mentions “lamentation.”

Matthew identifies the author of this quotation as Jeremiah.  Verse 2.17:  “Then was fulfilled that which was spoken by Jeremy the prophet, saying ...”

This is Jeremiah 38.15 in the LXX.