大乘起信論裂網疏 4.78

4.78

一切諸佛在因地時者，即與我等同為凡夫時也。由信自心有真如法，便能發大慈悲四弘誓願，修行六度四攝等行，普救眾生盡一切劫，即是修行觀門；如實了知自他平等，而亦不取眾生之相，即是修行止門。止觀二門，修必並運。後修信中，是約自行之功，故先明止；今文為顯化他之用，故先明觀也。又此中觀物同已，即《般若》中發廣大心。普皆救脫，即《般若》中發第一心。了知自他平等，即《般若》中發愛攝心，亦名常心。而亦不取眾生之相，即《般若》中不顛倒心。只此四心念念相應，名為大方便智，故能證體而起用也。然此自在差別作用，在凡夫人所見，則名世諦，以其有分別故。在聖人心中所見，即唯第一義諦，以其無分別故。故曰：所言二諦，其實是一。譬如醉人妄見屋轉，謂有轉屋及不轉屋。其實醉人所見轉屋，即是醒人所見不轉之屋，無二屋也。

"When all Buddhas were on the causal stage" means when they were ordinary beings just like us. Through faith that one's own mind has the principle of tathatā, one is able to generate the great compassion of the four universal vows, practice the six perfections, the four means of embrace, and other practices, and universally save sentient beings through all kalpas—this is the cultivation of the approach of contemplation. Truly knowing the equality of self and other and yet not grasping at the marks of sentient beings—this is the cultivation of the approach of calming. The two approaches of calming and contemplation must be exercised together in practice. Later, in the cultivation of faith, because it concerns the efficacy of one's own cultivation, calming is explained first; here in this text, in order to display the function of transforming others, contemplation is explained first. Furthermore, here, "viewing beings as equal to oneself" corresponds in the Prajñā[pāramitā] to generating the vast mind. "Universally delivering them all" corresponds in the Prajñā[pāramitā] to generating the supreme mind. "Knowing the equality of self and other" corresponds in the Prajñā[pāramitā] to generating the lovingly embracing mind, also called the constant mind. "And yet not grasping at the marks of sentient beings" corresponds in the Prajñā[pāramitā] to the non-deluded mind. Merely having these four minds in accord from thought to thought is called the wisdom of great skillful means; hence one can realize the essence and give rise to function. However, as for this autonomous and differentiated functioning, in what ordinary beings see, it is called conventional truth because they have discrimination. In what is seen within the mind of the sages, it is solely the ultimate truth because they are without discrimination. Therefore it is said: What are called the two truths are in fact one. It is just like a drunkard falsely seeing the house spin around, claiming that there is a spinning house and an unspinning house. In reality, the spinning house seen by the drunkard is precisely the unspinning house seen by the sober person; there are not two houses.