"As time passes, everything changes – culture, people’s mentality and behavior, the environment and so forth – so the way that the teachings are presented also has to change. Today, when everything moves so fast, we can’t necessarily use methods that in earlier times took a long time to accomplish. Lord Buddha himself said that when the culture changes, delusion, mentality and behavior also change, so even the vinaya rules have to be adjusted, because in their original form they may no longer benefit. We should therefore understand that Lord Buddha taught in order to help beings according to their individual need, so naturally, as time passes, the way his teachings are presented and practiced might also have to change. Even in times of nuclear war there’d still be a skillful way to practice Dharma.
If the teachings are not suited to the times and way of life, they’re very difficult to practice. I mean, if the only way to reach enlightenment was to ride a snow lion around Amsterdam we’d really be in trouble.
However, the practice of tantra is very well suited to twentieth century life. Life today is full of pleasure but we also have a tendency to be easily confused and dissatisfied. Therefore we need a method whereby we can transform the energy of all our everyday life experiences into the path to enlightenment; we desperately need that kind of skill. So that’s what tantra offers us."
From: Vajrayana, by Lama Yeshe as published in Mandala Magazine