Genesis 18.18
Septuagint

Abraam de ginemenoV estai eiV eqnoV mega kai polu, kai 

eneuloghqhsontai en autwpanta ta eqnh thV ghV

New Testament - Galatians 3.8

proidousa de h grafh oti ek pistewV dikaioi ta eqnh o qeoV, proeuhggelisato tw Abraam oti 
eneuloghqhsontai en soi panta ta eqnh:

Septuagint

But Abraam shall become a great and populous nation, and in him shall all the nations of the earth be blessed

New Testament

And the scripture, forseeing that God would justify the Gentiles by faith, preached the gospel beforehand unto Abraham, saying, In thee shall all the nations be blessed

Masoretic Text

seeing that Abraham shall surely become a great and mighty nation, and all the nations of the earth shall be blessed in him

Comments:  The NT, LXX and MT agree.