There is a major anachronism that occurs in this discussion. The assumption that EP was just as rigid in the Westminster days as it is in modern EP contexts. Keeping out Roman Catholic hymns is a bit different than excluding "Holy, Holy, Holy," "Great Is Thy Faithfulness," or "Rock of Ages." As these kinds of hymns did not exist at the time of the Westminster Assembly, it is anachronistic to say, a priori, that the Westminster divines would exclude them. This is not the same category as excluding doxologies from the Psalms. In the Psalter portion of a hymn-book, one would expect nothing but Psalms. I would hope that all of us on the PB would prefer the 150 Psalms to Roman Catholic hymns. According to the index in volume 4 of CVD's work, there is no explicit definition of psalms in the divines' discussion of chapter 21.5. The Westminster Annotations on Ephesians 5:19 do not limit "psalms, hymns, and spiritual songs" to the 150 Psalms. This is their comment: "But it seemeth most probable, that by Psalms he meaneth the Psalms of David set to the harp or psaltery, by Hymns, certain Ditties made upon special occasion; and by spiritual Songs, such as were not composed before-hand, and prick'd before them with musical notes, but such as men endited by an extraordinary gift."
The directory for public worship only gets as specific as saying "a psalm book." Psalm books sometimes had non-psalmic material in it. As I said before, if the Westminster divines only had what was eventually the 1650 Scottish Psalter in mind, then it proves too much.
Interestingly, Thomas Ford (a member of the Westminster Assembly) has this to say about the Psalms: "I am not so much against composing, as imposing; when men set up their own new songs, and shut out David's Psalms. Suppose it is lawful for men of spiritual minds to indict a Psalm, and then comment it to others, and sing it; yet, for argument's sake, it will not follow that therefore we must not sing the Psalms of David. Objection. But here again it is objected, that we conceive prayers, and therefore may as well conceive Psalms too, for praising God on occasion. Solution. I will not say it is unlawful to conceive and compose a Psalm upon occasion. But I say again there is no reason that our conceived Psalms should shut out David's" (see the McMahon version, p. 40). It is plain from this quotation that a member of the Westminster Assembly viewed the term "psalms" not exclusively, and even used it of non-inspired compositions. Winzer conveniently leaves out this portion of Ford's treatise in his treatment of Ford.
It is quite astonishing to me that Winzer accuses Needham of misrepresenting John Lightfoot, but then quotes the relevant portion of Lightfoot, which says precisely what Needham said it says. Needham says that Lightfoot understood by the three terms in Colossians 3:16 the Psalms, and other songs in Scripture. Winzer says Lightfoot was quoting someone he disagreed with, and that Lightfoot preferred a different interpretation. But when Winzer quotes Lightfoot, it is evident that Lightfoot agreed with the majority view when he says, "Others differ upon particulars, but agree upon this, that by these three are meant the Psalms of David, and other Songs in Scripture." Winzer even acknowledges that his reading of Lightfoot may have been wrong. He offers zero evidence that Lightfoot disagreed with the others he was quoting. Winzer is further unclear on whether Colossians 3:16 refers to public worship or not. For many of his arguments, he seems to assume that it is, and he argues the standard EP position on the passage. But when Needham quotes Poole's commentary (the section on Colossians 3:16 was written by the continuators), all of a sudden, Needham has to prove that Paul was talking about public worship.
I find it fascinating that Chris says that it is not proper to use sources outside the work of the Assembly if the Assembly's work is itself clear, but then gives a free pass to Winzer in this regard, who quotes plenty of sources that are outside the Assembly's direct work (confer his discussions of Ford, Burroughs, Rutherford, Edwards, Dickson, Calamy, Baynes and others). Given Winzer's distortion of Ford's position, I would not trust his analysis of others, either. If the Assembly's work was so clear, then why did Winzer need to quote sources outside the Assembly's work itself? As another example, take his quotation of Manton, which conveniently ignores this quotation on the previous page: "I confess we do not forbid other songs; if grave and pious, after good advice they may be received into the Church." He goes on to argue that the Psalms are the best songs and most fitting to be sung, which I would hope any IP'er could agree with. But Manton's position is hardly EP. Winzer quotes Cuthbert Sydenham (not Sydenham Cuthbert as in Winzer) also misleadingly. Sydenham was a Scripture song only advocate, not EP. He argues that the songs, hymns and spiritual songs are the Psalms of David "and such other which are found in Scripture penned by holy men upon special occasions" (McMahon, 156). The evidence even inside the Assembly's work is not nearly as clear to one who doesn't already hold EP. No doubt it seems overwhelming to one already convinced of the position. But many holes can be poked in the arguments. The fact is that the Westminster divines weren't NEARLY as strict as their erstwhile spiritual descendants, and it is anachronistic to assume that they were as strict as modern-day EP'ers.