From Lewis Bayly, The Practice of Piety:
Rules to be observed in Singing of Psalms.
1. Beware of singing divine psalms for an ordinary recreation, as do men of impure spirits, who sing holy psalms intermingled with profane ballads: They are God´s word: take them not in thy mouth in vain.
2. Remember to sing David´s psalms with David´s spirit (Matt. xxii. 43.)
3. Practise St. Paul´s rule"”"œI will sing with the spirit, but I will sing with the understanding also." (1 Cor. xiv. 15.)
4. As you sing uncover your heads (1 Cor. xi. 4), and behave yourselves in comely reverence as in the sight of God, singing to God in God´s own words; but be sure that the matter make more melody in your hearts (Eph. v. 19; Col. iii. 16) than the music in your ear; for the singing with grace in our hearts is that which the Lord is delighted withal, according to that old verse:
Non vox, sed votum; non miisica chordula, sed cor:
Non clamans, sed amana, psallit in aure Dei.
"˜Tis not the voice, but vow;
Sound heart, not sounding string;
True zeal, not outward show,
That in God´s ear doth ring.
5. Thou mayest, if thou thinkest good, sing all the psalms over in order, for all are most divine and comfortable; but if thou wilt choose some special psalms, as more fit for some times and purposes, and such as, by the oft usage, thy people may the easier commit to memory.
In the morning, Psalm iii. v. xvi. xxii. cxliv. In the evening, Psalm iv. cxxvii. cxli. For mercy after a sin committed, Psalm li. ciii. In sickness or heaviness, Psalm vi. xiii. lxxxviii. xc. xci. cxxxvii. cxlvi. When thou art recovered, Psalm xxx. xxxii. On the Sabbath day, Psalm xix. xcii. xcv. In time of joy, Psalm lxxx. xcviii. cvii. cxxxvi. cxlv. Before sermon, Psalm i. xii. cxlvii. the 1st and 5th parts of the cxix. After sermon, any Psalm which concerneth the chief argument of the sermon. At the communion, Psalm xxii. xxiii. ciii. cxi. cxvi. For spiritual solace, Psalm xv. xix. xxv. xlvi. lxvii. cxii. cxvi. After wrong and disgrace received, Psalm xlii. lxix. lxx. cxl. cxliv.