A rather common argument against exclusive psalmody is based on the assumption that metrical versions of the Psalms for singing (i.e., the Psalms are translated in a manner so they can be set to music and thus are made to rhyme, etc.) are really not translations of the Psalms but are at best gross paraphrases of the original Hebrew. Thus, it is argued that the singing of metrical Psalms is little or no different than singing uninspired hymns which are based on Scripture or which teach redemptive history. In other words, both are human compositions and if one is permissible then so is the other.
While this argument is common, it is refuted in a number of ways. First, note that the whole argument is based on an unbiblical, immoral analogy. The argument assumes that if a group of people distort the original meaning of the Psalms with a bad or faulty translation this somehow permits other people to use man-made hymns. In other words, if group A does something wrong, group B can also do something wrong. If it is indeed true that some Reformed believers are using sloppy, poorly translated metrical versions of the psalms, then our response as Christians should never be “Let us do likewise” or even worse “Let us go a step further by ignoring the inspired psalms altogether.” Rather it must be, “Brother, repent! There are excellent, faithful Psalters available. You do not need to use a defective translation!” To those brothers who use this argument we ask one simple question, “Does the fact that some churches use terrible paraphrases of the Bible for the Scripture reading in public worship justify the use of non-inspired Christian writings instead of the Scripture?” No, of course not! Then, poor translations of the Psalms do not justify man-made hymns.
Second, many who use the metrical Psalm argument assume that metrical versions of the Psalms (by virtue of the fact that they must be phrased to rhyme and fit music) are of necessity bad translations. In other words, it is impossible to be faithful to Scripture while using a metrical Psalter. This argument must be rejected because it is based on a false assumption. Metrical Psalms can and have been faithfully and accurately translated from the original tongue. Further, even if it were true it would not justify the use of man-made hymns. If a Reformed believer holds that metrical Psalms are inherently defective and thus unfaithful to the scriptural command to sing Psalms in worship, then instead of turning to uninspired compositions he should chant the Psalms in their original phrasing (i.e., out of one of the more literal translations of the Bible) during worship.
(Adapted from Bryan Schwertley's Exclusive Psalmody: A Biblical Defense)
SEE ALSO: http://www.fpcr.org/blue_banner_articles/paraphrases.htm
And from an old Covenanter:
"That our Meeter-Psalmes are no device of men, seeing they are the same in substance and sense, with these in prose, without any greater variation, then the application of the command of singing to us Scots-men, doth both require and warrant, is obvious to any mans candid reflection: As to the possibility of singing in Prose, as well as in Rime, I have already acknowledged it, and when you shall make it plainly and safely practicable, I presume none will dissent." -- Robert McWard (1633-1687), "The True Non-Conformist" (1671), p. 27