Manava Dharmashastra 2.103

2.103

na tiṣṭhati tu yaḥ pūrvāṃ nopāste yaś ca paścimām
sa śūdravad bahiṣkāryaḥ sarvasmād dvijakarmaṇaḥ //

But he who does not (worship) standing in the morning, nor sitting in the evening, shall be excluded, just like a Sudra, from all the duties and rights of an Aryan.