妙法蓮華經玄義 1.86

1.86

由因致果，果為因所辦。若從能辦，以因為宗；若從所辦，以果為宗。二義本是相成，不得單取。又迹本二文，俱說因果故。

Through the cause one attains the fruit; the fruit is accomplished by the cause. If viewed from what accomplishes, cause is the central purport; if viewed from what is accomplished, fruit is the central purport. The two meanings originally complement each other and cannot be taken singly. Furthermore, the texts of both the traces and the original source teach both cause and fruit.