After Piccolo wins the after life tournament he is allowed to train with the Grand Old Kai. But this is mostly just mediating.
Dende tells Vegeta where the next dragonball is and that the Elder Namekian is also there. He tells him that there should be plenty of other Namekians that can show him where the dragonballs are. The elder Guru is waiting for Vegeta as he arrives. Vegeta : is thinking about how to get what he wants with out just taking it because he dose need a guide and they are technically on the same side : Guru tells Vegeta that he has already read his mind and knows why he is there. Vegeta begins to say...........Soooo will you help me? But is cut off Guru sayes He knows that Vegeta may be the only hope for the Namekians but that Vegeta will have to find peace in his own mind to truly be helped by him. Vegeta sayes Help? I just want a guide. Guru sayes Have I not made it clear that I know that? Vegeta is surprised by Guru giving him attitude but he smiles and ask how else dose he need to be helped then? Guru tells him that he can balance him out if he promises that he will do every thing he can to stop Frieza. Vegeta : It would seem that you should already know I WILL KILL THAT MONSTER. Guru : It is difficult for me to help a murderer. Could you atleast pretend you are doing this to save my people or even just yourself. Vegeta : I don't know how much of my mind you've read Old man but I AM doing this to save myself and if I happen to save you too than so be it. Guru : Promise me that you will try to be motivated by more than your revenge and that you see my people's lives matter. Vegeta : I promise that you've pushed me to my limits give me a guide to the dragonballs NOW. ::: the sun is setting ::: Guru : I will give you a guide in the morning but if you don't make that promise I fear we will all die. King Vegeta came to Vegeta in his sleep and told him that Saiyan pride is a strong source of power but that Frieza has an army and that Vegeta needs one too. There is more to the conversation but we can't hear it. In the mourning Vegeta sayes to Guru : I've helped Frieza kill more peoples than I can remember I'm here to kill him not your people. If you can help me I will be thankful for it if not I must move on. Guru : I can and I will.
Grand old Kai tells Piccolo that a fighters power level is based on ten different attributes. Some of Piccolo's levels are as low as a 3 and some are as high as a 7 his average level is a 5. He also sayes that he has balanced out his power so that now all ten attributes are at 5. But that he can only keep him balanced while Piccolo is in his presence. However if Piccolo trains now he may maintain the balance and possibly even raise his power.
Guru explains the same thing to Vegeta in almost the same words. Guru holds Vegeta and tells him that this might be painful. After a few min. right when Vegeta is about to pull away because he hasn't felt anything. Guru lets go and stumbles backwards in pain. Vegeta also stumbles back in pain but then feels great. Guru's entire body flickers which shocks Vegeta and the Namekian on lookers. It turns out that Guru's power not only balances out the effected but also raises them to which ever level was the highest at the cost of some of Guru's own life force.