Isaiah 42.1-3
Septuagint

Iakwb o paiV mou, antilhyomai autou:   Israhl o eklektoV mou, prosedexato auton
h yuch mou:  edwka to pneuma mou ep auton, krisin toiV eqnesin exoisei.
ou kekraxetai, oude anhsei,
oude akousqhsetai exw 
h fwnh autou. 
kalamon teqlasmenon ou suntriyei
kai linon kapnixomenon ou sbesei, 
alla eiV alhqeian exoisei krisin

New Testament - Matthew 12.18-20

idou o paiV mou on hretisa, o agaphtoV mou eiV on eudokhsen

h yuch mou:  qhsw to pneuma mou ep auton, kai krisin toiV eqnesin apaggelei.
ouk erisei oude kraugasei,
oude akousei tiV en taiV plateiaiV 
thn fwnhn autou. 
kalamon suntetrimmenon ou kateaxei
kai linon tufomenon ou sbesei, 
ewV an ekbalh eiV nikoV thn krisin

Septuagint

Jacob is my servant, I will help him:  Israel is my chosen, my soul has accepted him; I have put my Spirit upon him; he shall bring forth judgment to the Gentiles. He shall not cry, nor lift up his voice, nor shall his voice be heard without.  A bruised reed shall he not break, and smoking flax shall he not quench; but he shall bring forth judgment to truth

New Testament

Behold, my servant whom I have chosen; My beloved in whom my soul is well pleased:  I will put my Spirit upon him, And he shall declare judgment to the Gentiles. He shall not strive, nor cry aloud; Neither shall any one hear his voice in the streets.  A bruised reed shall he not break, And smoking flax shall he not quench, Till he send forth judgment unto victory

Masoretic Text

Behold, my servant, whom I uphold; my chosen, in whom my soul delighteth:  I will put my Spirit upon him; he will bring forth justice to the Gentiles.  He will not cry, nor lift up his voice, nor cause it to be heard in the street.  A bruised reed will he not break, and a dimly burning wick will he not quench:  he will bring forth justice in truth

Comments:  The NT, LXX and the MT disagree.  The NT author clearly did not base his quotation on the LXX.  He also strays from the MT.  The phrase from the New Testament Greek translated as “in whom my soul is well pleased” is found in Theodotion’s translation of Isaiah 42.1.