Psalm 2.1-2
Septuagint



inati efruaxan eqnh, kai laoi emelethsan kena; paresthsan oi basileiV thV ghV, kai oi arconteV sunhcqhsan epitoauto kata tou kuriou, kai kata tou cristou autou. diarrhxwmen touV desmouV autwn, kai aporriywmen af hmwn ton zugon autwn

New Testament - Acts 4.25-26

o tou patroV hmwn dia pneumatoV agiou stomatoV David paidoV sou eipwn: 
inati efruaxan eqnh kai laoi emelethsan kena; paresthsan oi basileiV thV ghV kai oi arconteV sunhcqhsan epi to auto kata tou kuriou kai kata tou cristou autou

 

Septuagint

Wherefore did the heathen rage, and the nations imagine vain things?  The kings of the earth stood up, and the rulers gathered themselves together, against the Lord, and against his Christ; saying, Let us break through their bonds, and cast away their yoke from us

New Testament

who by the Holy Spirit, by the mouth of our father David thy servant, didst say, Why did the Gentiles rage, and the peoples imagine vain things?  The kings of the earth set themselves in array, and the rulers were gathered  together, against the Lord, and against his Anointed

Masoretic Text

Why do the nations rage, and the peoples meditate a vain thing?  The kings of the earth set themselves, and the rulers take counsel together, against Jehovah, and against his anointed

Comments:  The LXX and the NT are in exact agreement.  The MT has the rulers taking counsel together, while the LXX and the NT simply have them gathering.