Malachi 3.1
Septuagint

idou exapostellw ton aggelon mou, kai epibleyetai odon pro proswpou mou
 

New Testament - Matthew 11.10

idou egw apostellw ton aggelon mou pro proswpou sou,
oV kataskeuasei thn odon sou emprosqen sou

Mark 1.2

idou egw apostellw ton aggelon mou pro proswpou sou,
oV kataskeuasei thn odon sou 

Luke 7.27

idou egw apostellw ton aggelon mou pro proswpou sou,
oV kataskeuasei thn odon sou emprosqen sou

Septuagint

Behold, I send forth my messenger, and he shall survey the way before me

New Testament

Matthew 11.10:  Behold, I send my messenger before thy face, Who shall prepare thy way before thee

Mark 1.2:  Behold, I send my messenger before thy face, Who shall prepare thy way

Luke 7.27:  Behold, I send my messenger before thy face, Who shall prepare thy way before thee

Masoretic Text

Behold, I send my messenger, and he shall prepare the way before me

Comments:   The NT and the MT agree.  The LXX replaces “prepare” with “survey.”

Mark attributes Malachi 3.1 to Isaiah in many NT texts. Isaiah 40.3 immediately follows these lines in Mark’s gospel.  Matthew and Luke preface the quotation by saying “this is he, of whom it is written.”

Codex Alexandrinus (with others) includes egw, with the NT.