Rejoicing means being happy to see the happiness of others; the simplest and sharpest way to slice through our jealousy, competitiveness, and pride. We just see someone who is enjoying good conditions or who possesses good qualities and we think ‘I’m glad for you.’ They’re happy; we share in their happiness.
In my experience, it’s simple as long as we don’t get caught up in thinking too much – you know, all that ‘But they don’t deserve it / I worked much harder than them / I try just as hard but no-one is praising me.’ One of the main points of rejoicing is to stop all that thinking about ourselves! Try instead just to think: ‘There’s little enough happiness in the world, I’m glad I get to see a little bit of it.’
As a matter of fact, everyone does deserve the happiness they enjoy, because anything good that people experience is a result of their previous positive actions, or good karma. In Great Treasury of Merit, Geshe-la says:
Shantideva says that there are two things we can rejoice in: virtue, which is the cause of happiness, and happiness itself. It is not enough just to rejoice when we see others engaging in virtue, we also have to feel happy when we see them experiencing the results of their virtue. A Bodhisattva is like a mother who delights in the happiness and good fortune of her children. If we want to become Bodhisattvas we must also learn to delight in the happiness, success, relationships, possessions, and even the laughter of others.
Remembering that they created the causes for their present good conditions encourages us to see the good in others, and it also encourages us to emulate their good qualities and positive actions. In the same section as quoted above, Geshe-la uses the example of two friends who are practising Buddhism together, one emphasising meditation and the other emphasising study. If they rejoice in each other, each will be encouraged to develop a more balanced practice and there will be no basis for that pride which decides ‘my way of doing things is the only right way.’
We can also rejoice in our own positive actions whenever we are feeling a bit discouraged. Think of all the good causes we have created: every time we meditate, even if it doesn’t go well, we have created the cause to experience inner peace in the future. It may not feel like we’re getting far, but we are capable of creating an extraordinary amount of good fortune: just look at this human life. In our previous life, we planted the seeds for all the incredible conditions we have today. That means that last time round, we were a really good person. If we managed then, we can certainly do it again now!