“More and more people are seeing this: they enter the mystery, abandoning themselves to God”. 

Ps 40:3 EHP 
It may sometimes seem as if the Christian community is a quiet little group on the edge of society. Like a bowling club or a stamp collectors’ club it makes no impact on society at large, just providing a pleasant and harmless outlet for people with a special interest. If this is how it is, then there is something sadly lacking in the Christian community and in its worship. 
The psalm-writer was only one member of the community of faith where he lived. But he was not the only one to whom God had given a new song to sing. Others joined him in his praise and glory of God. And he was conscious that this combined action made an impact on those who were not God-fearers in the community. He knew that they observed the worshipping community of his day and took note of what they were up to. If the outside observers were positively impressed, then they would want to become part of the worshipping people themselves. What the worshippers did both in their worship and in their normal lives was a witness to other people to the power and grace of God. 
Christian believers have always known this too. They know it is their duty to witness to “outsiders” and to tell them of what God has done in their lives. They know too that one really good effective witness is worth fifty sermons from preachers. The disciples of Jesus went onto the streets of Jerusalem on the day of Pentecost to tell the assembled Jewish worshippers what God was doing. True witnesses still do it today. 

PRAYER THOUGHT Lord, make me a witness to your grace and power.