p. 245
ब्राह्मणानां तपः समृद्धमन्येषां तावदेव तत् ॥
In plain words
In the brāhmaṇas, tapas comes to full ripeness; in others, that tapas reaches only so far and no further.
Close to the Sanskrit
Of the brāhmaṇas, tapas is fully grown; of others, that is only so much.