Manusmriti
वृद्धांश्च नित्यं सेवेत विप्रान् वेदविदः शुचीन् । वृद्धसेवी हि सततं रक्षोभिरपि पूज्यते ॥ ३८ ॥
Let him daily worship aged Brahmanas who know the Veda and are pure; for he who always worships aged men, is honoured even by Rakshasas.
english translation
vRddhAMzca nityaM seveta viprAn vedavidaH zucIn । vRddhasevI hi satataM rakSobhirapi pUjyate ॥ 38 ॥
hk transliteration by Sanscript