What is Lo Jong mind training? A friend of mine recently mentioned Lo Jong mind training to me, when I asked my teacher he told me not to worry about it.

Would anyone be willing to explain what it is and what it is used for?
lo= mind, and jong=learn, train, purify. It is a combination of pithy instructions for training the mind on the Buddhist path, particularly for those who have taken bodhisattva vows, but can be used by any practitioner. It trains the mind to awaken compassion for self and others. Rather than dwelling on obstacles, crying mea culpa, one uses them to learn by taking on the suffering of self and others as a training exercise to improve the depth of ones compassion. The steps to mind training together with explanation are too extensive for this forum, however, Jamgon Kontrul's "The Great Path to Awakening" is a good place to find more in depth answers.