Jesus warned about losing our usefulness to God.

Luke 14:34-35

34 Jesus also said, “You are like [MET] salt, which is useful to put on food. But ◄salt certainly cannot be made {you certainly cannot make salt} to taste salty again if it stops tasting salty!/can salt be made {can you make salt} to taste salty again if it quits tasting salty?► [RHQ] 35 If salt does not taste salty any more, it is not good for the soil or even for the manure heap. People throw it away. The same thing will happen to you if you become useless to God. If you want to understand what I just said [IDM], you must consider carefully what you have heard!”