At verse 6 God himself suddenly speaks to his people, reminding them of his faithfulness to them in the past in freeing them from slavery. He further reminds them of his promises of protection if only they would be faithful to him and his ways, avoiding the sin of idolatry and worshipping him alone. Here his tone is reminiscent of the final verses of Psalm 95. God laments that his people would not listen, and so he left them to their sinful ways. He reiterates his promise, which is still on offer to those who love him and obey his commands.
The last two verses see another shift of voice, as the psalmist echoes God's threat of punishment and his promise of prosperity.
Some Christians are uncomfortable singing in God's voice, that is, in taking on their own lips the words of God as if they themselves were God. I've heard this complaint made most often of contemporary Roman Catholic hymns, such as Be Not Afraid and I Will Be With You, but also of Lord of the Dance, which has found its way into a number of denominational hymnals. Those who do not like to sing in God's voice should remind themselves that those singing the psalms necessarily find themselves doing so on occasion. Psalm 81 is a good example of this.
Singing in the “voice of God” becomes problematic when a lyricist puts words into God’s mouth — that is, either loosely paraphrases Scripture beyond recognition (similar to many based-on-a-true-story films), or worse, completely makes something up to place into God’s mouth (and subsequently our mouths when we sing it, and our ears when we hear it). At best, it is an imposition of private revelation on an act of public worship; at worst, it is a lie. Both are unacceptable, and neither are guaranteed to be God’s Word — for if “it is He Himself who speaks when the holy scriptures are read in the Church”, who speaks when the holy scriptures are paraphrased or someone puts words into God’s mouth?My recommendation? Sing in the voice of God without worry if it’s really and truly the Word of God you’re singing, for God is speaking to you even as you sing — voice of God or not.
I found the Genevan version of Psalm 81 not especially easy to work with, mostly because the stanzas are short, as are the phrases within each stanza. The metrical pattern is 56 55 56. My own text thus contains ten stanzas for what is otherwise a fairly short psalm. The tune is in the ionian mode, which is equivalent to our major scale.
Immediately below the Komlói Pedagógus Kamarakórus (Teachers' Chamber Choir of Komló, Hungary) performs Psalm 81 followed by Psalm 119: