Jesus sums up commonsense carefulness in a disciple as infidelity. If we have received the Spirit of God, He will press through and say — “Now where does God come in in this relationship, in this mapped-out holiday, in these new books?” He always presses the point until we learn to make Him our first consideration. Whenever we put other things first, there is confusion.
“Take no thought…” — don’t take the pressure of forethought upon yourself. It is not only wrong to worry, it is infidelity, because worrying means that we do not think that God can look after the practical details of our lives, and it is never any thing else that worries us. Have you ever noticed what Jesus said would choke the word He puts in? The devil? No, the cares of this world. It is the little worries always. I will not trust where I cannot see, that is where infidelity begins. The only cure for infidelity is obedience to the Spirit.
The great word of Jesus to His disciples is abandon.