Zechariah 9.9
Septuagint

caire sfodra 
qugater Siwn, 
khrusse qugater Ierousalhm: 
idou o basileuV ercetai soi
dikaioV kai swzwn, autoV 
prauV, kai epibebhkwV, epi upozugion kai pwlon neon
 

New Testament - Matthew 21.5

eipate th 
qugatri Siwn:

idou o basileuV sou ercetai soi

trauV kai epibebhkwV epi onon kai epi pwlon uion upozugiou

John 12.15

mh fobou, qugathr Ziwn:
idou o basileuV sou ercetai,
kaqhmenoV epi twlon onou

Septuagint

Rejoice greatly, O daughter of Sion; proclaim it aloud, O daughter of Jerusalem; behold, the King is coming to thee, just, and a Saviour; he is meek and riding on an ass, and a young foal

New Testament

Matthew 21.5:  Tell ye the daughter of Zion, Behold, thy King cometh unto thee, Meek, and riding upon an ass, And upon a colt the foal of an ass

John 12.15:  Fear not, daughter of Zion:  behold, thy King cometh, sitting on an ass’s colt

Masoretic Text

Rejoice greatly, O daughter of Zion; shout, O daughter of Jerusalem:  behold, thy king cometh unto thee; he is just, and having salvation; lowly, and riding upon an ass, even upon a colt the foal of an ass

Comments:  The NT, LXX and the MT agree.  The beginning of this quotation is actually from Isaiah 62.11.

Some LXX manuscripts include sou in “basileuV sou,” in agreement with the NT.