On page 29 of "Battling Unbelief" by John Piper, he says that Matthew 6:25 is "an argument from the greater to the lesser":
25“Therefore I tell you, do not be anxious about your life, what you will eat or what you will drink, nor about your body, what you will put on. Is not life more than food, and the body more than clothing? ESV
I've always read it the way it's rendered in the NET translation:
Isn’t there more to life than food and more to the body than clothing?
which is more like a call for perspective - though Piper's interpretation certainly sits better with the theme of trusting in God's provision in this section.
Which is the right interpretation?