Psalm 34:1

I will bless the Lord at all times; His praise shall continually be in my mouth.

Sometimes we do not say thank you enough to God.  We tend to be like ungrateful teenagers forgetting all that our parents have done for us.  It is the same with God; we did not see the sacrifice of Jesus on the cross, but we benefit from that sacrifice.  Our praise shows our love and thankfulness for all that God has done.