The psalmists insistence that we praise God bother Lewis. It seems like god needs praise much like a vain woman needs compliments. But, then he realized that it is in our nature to praise and we do it all the time for natural things. Praise is the consummation of the enjoyment of a thing or a person. Plus, it is in the act of worship, and praise is worship, that God often speaks to us. There is no bargaining with God here. That is, if we praise him, we don’t get something back.