大乘起信論義記 3.311

3.311

From “faith in this way” onward concludes the rank. First, “enter the assembly of the definitively fixed, are non-retrogressing” shows that there is no falling away below; that is, entering the rank of the abode of initial generation of the mind among the ten abodes, one does not fall into the station of ordinary beings and the small [vehicle]. As for “are called those who abide in the lineage of the Tathāgatas, conjoined with the correct cause,” this clarifies that they have attained [virtue] above; that is, abiding in the rank of the nature of habit-practicing, their practice conforms to the cause of internal perfuming, hence it is called the “correct cause.” Furthermore, from this rank onward, they are certain to attain the fruition, hence it is called the “correct cause,” because they will no longer retrogress or fall away.