From Mindfulness To Buddhahood

常生大乘善信,
自知我是未成之佛,
诸佛是已成之佛,
发菩提心, 念念不去心。

– 释迦牟尼佛
   (梵网经)

Constantly giving rise to good faith in the Great Vehicle [for delivering one and all to Buddhahood], personally know that I am [you are] a yet to be accomplished Buddha, that all Buddhas are already accomplished Buddhas, and give rise to Bodhicitta [the aspiration for Buddhahood], with every thought never away from this aspiration.

– Sakyamuni Buddha
  (Brahma Net Sutra)

念念心念佛,
念念心成佛。

With thought to thought, the mind being mindful of a Buddha, with thought to thought, the mind [eventually] becomes a Buddha.

– Stonepeace

诸佛如来是法界身，
入一切众生心想中。
是故汝等心想佛时，
是心即是三十二相，八十随形好。
是心作佛，是心是佛。
诸佛正遍知海，从心想生。

– 释迦牟尼佛
  (观无量寿佛经)

All Buddha Thus Come Ones, are the Dharma Realm’s Body, who enter all sentient beings’ minds’ contemplations within. Therefore, when you all have minds contemplating the Buddha, this mind is the same as his thirty-two forms, and eighty appearance-following excellences. It is the mind that becomes Buddha, and it is the mind that is Buddha. All Buddhas’ right all-knowing ocean, from the mind’s contemplation arises.

– Sakyamuni Buddha
  (Sutra Of Contemplation Of The Buddha Of Immeasurable Life)