The teacher or the spiritual friend
"I have met people who say "I have been waiting for my guru to appear for 15 years, when is he going to come? What shall I do in the meantime?" They become completely frustrated. He may or may not come. We must not wait until it happens. There is no need to become frustrated. Finding the teachings and the instructions are the most important things. This enables us to take the first step, to begin to learn. It doesn't matter so much from whom we receive the teachings. We learn and practise them for a while and when we have some insight into the teachings, and some experience of them, our trust in the teacher will grow naturally. So the more we know the teacher or the spiritual friend, the more our confidence grows. This confidence and trusting faith is not something that happens immediately, although this might be the case for some people. But usually it has to develop slowly. It's based on understanding, based on experience. So you don't just look at him or her and say: "Wow, I trust this person completely." Usually it does not happen like that. I have to understand the teacher and get to know him or her better. After some time the trust will develop. And the more my understanding of the teachings develops, the greater the trust will grow."
Ringu Tulku Rinpoche in "From Milk to Yoghurt, a recipe for living and dying", Heart Wisdom Series n°3, Bodhicharya Publications, 2009, p29