He is Worthy
The word tells us to "continually" offer up to God a sacrifice of praise. If we are to offer God continual praise, then our praise cannot be based on our emotions or the state of our lives because our emotions and seasons are not constant. Our praise must be based on something that remains constant if we expect it to be continual. That one constant thing we can base it on is that He is worthy all the time, no matter what happens.