Jesus did not come to teach about the world and how to succeed there; he came to teach about the ways and means of heaven. Efforts at interpretation that fail to realize that, however well-intentioned and ingenious, are fundamentally misoriented.
Still, there are occasions where what Jesus teaches about heaven finds echoes in what others teach about the world. When that happens, it isn’t because Jesus has now shifted His attention to the world; it’s because the world contains – or perhaps retains – elements of heaven.
One of these is His instruction concerning trust and confidence in the future. Regard the lilies of the field! Worldly writers also often encourage an optimistic attitude – The power of positive thinking! – and their evidence is how often it leads to worldly success, sometimes far exceeding reasonable expectations.
The difference is that the worldly writers are not claiming – unless they’re very foolish – that positive thinking invariably brings success. The world clearly and sometimes tragically can disappoint optimism. (That’s why many people choose pessimism as a life attitude, so that they’re never disappointed.) These writers are simply advocating a positive attitude as a very useful tool in one’s worldly dealings, along with discipline, self-control, energy, and so on. It increases the odds of success.
But Jesus is not talking about the world at all, except in the sense that there is something in the world that is a mirror – or perhaps residue – of something in heaven. And isn’t this amazing? There is so much we don’t know about heaven, but one thing we can say for certain is that, based on the Word of God, there is no pessimistic thinking there!
So we are encouraged by our Lord to cultivate a positive attitude in ourselves, not because it will help us get ahead in life or get the most out of life – although it very well may do both those things, and other good things besides – but because it will make the transition from here to heaven much more natural.