The quotations in the New Testament, from the Old Testament, are never made immediately from the Hebrew, but always from the Greek or the Aramaic version.
In respect to their origin, they may be conveniently divided into four classes: those which agree with both the Hebrew and the Septuagint; those which agree with the Septuagint against the Hebrew; those which agree with the Hebrew against the Septuagint; and those which agree with neither the Hebrew nor the Septuagint.
The second class, which is by far the largest, must be derived from the Septuagint; and the fourth, from the early Jewish Aramaic version, or from the Septuagint, by free citation. But the first and the third cannot be supposed to come from the Hebrew, for two reasons: first, the number and character of the cases in which the New-Testament writers depart from the Hebrew make it difficult to believe that they had this text before them; and, further, it is unlikely that Hebrew, which was a dead language in their time, was known to any of them except Paul, and his citations are almost uniformly from the Greek. Where, then, freedom of quotation will not explain the New-Testament deviations from the Septuagint, it is more natural to refer the citations, not to the Hebrew, but to the only other popular version of the Old Testament then in existence, -the Aramaic.
from page ix, Quotations in the New Testament