We sing about the holiness of God all the time. It's the attribute that is ascribed to the Lord more than any other attribute in the Bible. Indeed, his holiness inspires deep awe. At the same time, what a horribly-depressing, frightful thing for a sinner to sing about the holiness of God. It's the very attribute of the Lord that promises to rip us to shreds- condemn us now and forever.
BUT, if we have put on Christ's righteousness, we are free to embrace and even enjoy all of God- we can enjoy his holiness without its previously terrifying implications for sinners like you and me.
