The definition of mantra is "that which protects the mind." That which protects the mind from negativity, or that which protects you from your own mind, is called mantra.
Sogyal RinpocheWhen you have learned, through discipline, to simplify your life, and so practiced the mindfulness of meditation, and through it loosened the hold of aggression, clinging, and negativity on your whole being, the wisdom of insight can slowly dawn. And in the all-revealing clarity of its sunlight, this insight can show you, distinctly and directly, both the subtlest workings of your own mind and the nature of reality.
Sogyal Rinpoche{While meditating} I sit quietly and rest in the nature of mind; I don't question or doubt whether I am in the "correct" state or not. There is no effort, only rich understanding, wakefulness, and unshakable certainty. When I am in the nature of mind, the ordinary mind is no longer there. There is no need to sustain or confirm a sense of being: I simply am.
Sogyal RinpocheLight must come from inside. You cannot ask the darkness to leave; you must turn on the light.
Sogyal RinpocheWhat most of us need, almost more than anything, is the courage and humility really to ask for help, from the depths of our hearts: to ask for the compassion of the enlightened beings, to ask for purification and healing, to ask for the power to understand the meaning of our suffering and transform it; at a relative level to ask for the growth in our lives of clarity, peace, and discernment, and to ask for the realization of the absolute nature of mind that comes from merging with the deathless wisdom mind of the master.
Sogyal Rinpoche