大毘盧遮那成佛經疏 2.27

2.27

「復次祕密主！彼護戒生天，是第七受用種子」者，謂已能造齋施，見其利益，即知三業不善，皆是衰惱因緣，我當捨之護戒而住。由護戒故，現世獲諸善利，有大名聞、身心安樂，倍復增廣賢善，命終而得生天。譬如種果已成受用其實，故曰受用種子也。又云從一種子成百千果實，是一一果實復生若干，展轉滋育不可勝數。今此受用果心，復成後心種子，亦復如是，故曰受用種子也。

The sūtra says: "Furthermore, Master of Mysteries, their guarding the precepts and being born in heaven is the seventh: the seed of enjoyment." This means that having already performed fasting and giving and seen their benefits, one knows that the unwholesome actions of the three karmas are all causes of decline and distress: "I should abandon them and abide by guarding the precepts." Due to guarding the precepts, in the present life one obtains various wholesome benefits, great renown, peace of body and mind, and an even greater increase in virtuous goodness, and at the end of life one attains birth in heaven. Just as when a planted fruit has ripened, one enjoys its actual fruit, it is therefore called the "seed of enjoyment." It is also said that from a single seed hundreds of thousands of fruits are formed, and each fruit in turn produces further numbers, progressively multiplying beyond count. Now, this mind of enjoying the fruit again becomes the seed for subsequent minds; it is also like this, and therefore it is called the "seed of enjoyment."