Manava Dharmashastra 3.100

3.100

kṣatriyo brāhmaṇasyādhvanīno'pi prathamabhojanakāla upasthito'pi nātithiḥ ato na tasmai niyamato deyam | evaṃ vaiśyaśūdrābhyāmapi | sakhijñātī ātmasame, nātithī | guruḥ prabhuvadupacaryaḥ | ‘‘nivedya pacanakriyā’’ ityuktam (gautama 5 | 26) |

In a Brāhmaṇa’s house, the Kṣatriya is not called a ‘guest;’ nor the Vaiśya or the Śūdra, nor his friends or relations, or his Teacher.—(110)

Medhātithi’s commentary (manubhāṣya):
Even though a Kṣatriya, during his travelling, happen to arrive at the Brāhmaṇa’s house, at the time of breakfast,—he is not a “guest.” Hence it is not incumbent upon the Brāhmaṇa to offer food to him.

Similarly with the Vaiśya and the Śūdra.

The ‘friend’ and the ‘relation’ are one’s equals, not guests.

The ‘Teacher’ has to be served as the master; as described in the text—‘the act of cooking should be done after having offered to the Teacher’ (Gautama 5-26).—(110).