And let us consider how to stir up one another to love and good works
Hebrews 10:24 ESV
Something positive usually works better here.
The saying “the floggings will continue until morale improves” is funny when it is written on a tee shirt. But it isn’t funny or useful when trying to motivate people. When a team mate makes a good pass and you score — make sure you acknowledge them. When a team mate hustles and dives on the floor and comes up with a loose ball — let him know that you noticed the next time the ball is dead. This not only helps your team mate, but starts to educate the fans to know when someone did something they should cheer for.