金剛般若經贊述 1.148

1.148

為破此疑，故佛答云，未來有菩薩備三德者，曾已積集善根，故能生實想，亦不空說也。偈言「不空以有實」者，謂以有能生實想故，佛不空說也。

To refute this doubt, the Buddha answered that in the future there will be bodhisattvas endowed with the three virtues who have already accumulated roots of goodness; therefore they are able to give rise to true notions, and [the teaching] is also not spoken in vain. The verse says "not in vain, because there are true ones," meaning that because there are those able to give rise to true notions, the Buddha does not speak in vain.