Meaning: If you tell people what is right and moral then you should also hold yourself to the same standards. In essence, don’t be a hypocrite and DO as you recommend for others.
Polish meaning: Postępuj zgodnie z głoszonymi zasadami.
If you think it’s wrong to litter then you should practise what you preach and pick up that wrapper you just threw on the ground.
An example of use: If you think it’s wrong to litter then you should practise what you preach and pick up that wrapper you just threw on the ground.