If price is making higher highs, the oscillator should also be making higher highs. If price is making lower lows, the oscillator should also be making lower lows.
If they are NOT, that means price and the oscillator are diverging from each other. And that’s why it’s called “divergence.”
Divergence trading is an awesome tool to have in your toolbox because divergences signal to you that something fishy is going on and that you should pay closer attention.
Using divergence trading can be useful in spotting a weakening trend or reversal in momentum. Sometimes you can even use it as a signal for a trend to continue!