Sirach 15:9-10. "A hymn of praise is not fitting on the lips of a sinner, for it has not been sent from the Lord. For a hymn of praise should be uttered in wisdom, and the Lord will prosper it."

We are all sinners, so does this mean we should never sing hymns of praise to God? Of course not. This is, I think, very personal. It is speaking to the hypocrite - the unrepentant sinner who is singing praise not because he feels it or means it, not because it's been sent from the Lord, but for some other reason. It might be to make himself look better or feel better, or it might be because he finds himself in a situation where everyone else is praising God so he goes along, not meaning it.

The point here, though, is that since we are all sinners, we do not know if another's hymn of praise is heartfelt and sent from the Lord or is hypocritical. This is something only the singer and God know, the rest of us do not, but we know if our own hymn is heartfelt. God is warning us here - don't be hypocrites. It is better not to sing not to praise me at all if you don't mean it than to cause damage to yourself by singing my praises and then betraying me in your heart.

However, even though we are all sinners, if we are sincerely seeking God he responds, and this often inspires joy in us and causes us to sing his praises - how lucky are we that our God loves us even in spite of our sin!? This is the kind of hymn of praise that is uttered in wisdom - in understanding - and it will be prospered.