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 Tathagatas are the Dharma realm’s body, who enter all sentient beings’ minds’ thoughts within. This is as when the minds of yours and others think of [a] Buddha, your minds are the 32 forms and their 80 accompanying excellences. It is the mind that becomes [a] Buddha, it is the mind that is [a] Buddha. All Buddhas’ [immeasurably broad and deep] ocean of perfect and complete awakening from the mind’s thoughts arise.

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