The answer
This is the Coptic translation which is a very accurate translation as it coincides with the early Church fathers quotes of the Holy Scripture. St. Augustine’s commentary on the Holy Book of Psalm 38 mentions this same verse but with a different translation "And they cast Me forth, Thy Darling, even as a dead man in abomination." Please see http://www.ccel.org/fathers/NPNF1-08/augustine/psalms/PSALM38.htmClarke’s Commentary on this verse of the Holy Book of Psalm says "There is a remarkable addition to this verse in the Arabic: "They have rejected me, the beloved one, as an abominable dead carcass; they have pierced my body with nails." I suppose the Arabic translator meant to refer this to Christ. None of the other Versions have any thing like this addition; only the Ethiopic adds, "They rejected their brethren as an unclean carcass." St. Ambrose says this reading was found in some Greek and Latin copies in his time; and Theodouret has nearly the same reading with the Arabic: kai aperriyan me ton agaphton, wv nekron ebdelugmenon "And they cast me, the beloved, out, as an abominable dead carcass."
The verse Adam Clarke quotes is not in Van Dyke Arabic version but its translation is very similar to what we read today in the Psalm of Good Friday.
It is clear that this verse is a biblical text and not a liturgical one.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)