2 sentences

1. 你这是在自掘坟墓。

   nǐ zhèi shì zài zì​jué​fén​mù.

   You're digging your own grave.

   Source: OpenSubtitles

2. 这种不负责任的行为无异于自掘坟墓。

   zhè zhǒng bù fù zé​rèn de xíng​wéi wú​yì​yú zì​jué​fén​mù.

   This irresponsible behavior is no different from digging one's own grave.

   Source: Dong Chinese Dictionary