Instead we are completely covered with defilements and delusions. But these things which obscure Buddha Nature are not in the true nature of the mind. Similarly the obscurations are not in the nature of the mind, which is pure from the very beginning. This is why we say that every living being has Buddha Nature. This does not mean that we are already a Buddha, but that we have the seed of the Buddha.
Every seed has the potential to grow into a crop when it meets with the right conditions.
If we meet with the right conditions we all have the potential to become a fully enlightened Buddha. At present, because we do not see the true nature of the mind we are caught up in samsara, the circle of existence, and as long as we are caught in the circle we are not free from suffering. We will go on and on in this circle endlessly - unless we become enlightened. So the way to become free from suffering is to practise Dharma, the way of the Buddha. The method consists of taking refuge in the three jewels of the Buddha, the Dharma, and the Sangha.