瑜伽論記 6.126

6.126

初瑜伽處等，簡餘二乘，三乘皆有初瑜伽處，故有四處：一、種姓；二、數取趣；三、安立；四、世出世。於此四中，種姓為先，故言初也。瑜伽是觀行，種姓是觀行種子，種子能為現行、觀行作所依處，故言初瑜伽處種姓地。

Regarding "the first station of yoga" and so forth: this distinguishes them from the other two vehicles; all three vehicles have a first station of yoga, and thus there are four stations: first, gotra; second, person (pudgala); third, establishment; fourth, mundane and supramundane. Among these four, gotra comes first; hence it is called "first." Yoga is contemplative practice; gotra is the seed of contemplative practice. Seeds can serve as the locus of reliance for manifest activity and contemplative practice; hence it is called "the stage of gotra, the first station of yoga."