The Wheel of Sharp Weapons by Dharmarakshita, a ninth-century Indian scholar, combines teachings on lojong (mind training) with the lamrim, especially karma. This text is now freely available for download as a PDF file, produced by Piero Sirianni.
Lama Zopa Rinpoche often refers to the Wheel of Sharp Weapons and recommends that students read the text in order to understand and transform problems, which are created by the ego, the selfish mind.
In one letter to a student, Rinpoche says: "Please read the book called the Wheel of Sharp Weapons. This explains where problems like yours come from. Any problem you have, including depression, you can read about in this book, which explains how to use the problem to cut through the ego and self-cherishing thought. Self-cherishing is the main enemy to bodhicitta, which is what you need to achieve enlightenment and to enlighten all sentient beings."
Rinpoche also refers to the text in a teaching on Thought Transformation in Daily Life, where he says:
"The essence of thought transformation is as follows. First you think of the evolution of problems, that they come from your own self-cherishing thought, so that you don’t blame anything external for them. When you don’t put the blame outside, there is no problem; when you do, there is always a problem. Second, not only do you put all the blame on your self-cherishing thought, but you use every problem—cancer, AIDS, relationship problems, job problems, even failure in your Dharma practice—to destroy your self-cherishing. The problem is given to you by self-cherishing but rather then taking it upon yourself, you use it as an atomic bomb to destroy your self-cherishing. In this way the problem becomes a teaching on the Wheel of Sharp Weapons. This second point is very important. Rather than taking the problem upon yourself, you use it to destroy your self-cherishing mind, which brings all your failures: no enlightenment, no liberation, no good rebirth in your future life, and no happiness or relaxation even in your everyday life. You use all your problems to destroy self-cherishing."