Old Testament readings use the Septuagint , the Scripture the apostles quoted. Masoretic numbering shown for reference.Learn why
LXX

Malachi 3:1

Behold, I send forth my messenger, and he shall survey the way before me: and the Lord, whom ye seek, shall suddenly come into his temple, even the angel of the covenant, whom ye take pleasure in: behold, he is coming, saith the Lord Almighty.

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