Ṛgveda & Vedāṅga Jyotiṣa · c. 1500–1200 BCE
अमी य ऋक्षा निहितास उच्चा नक्तं ददृश्रे कुह चिद्दिवेयुः ।
अदब्धानि वरुणस्य व्रतानि विचाकशच्चन्द्रमा नक्तमेति ॥१०॥
Whither by day depart the constellations that shine at night, set high in heaven above us? Varuna's holy laws remain unweakened, and through the night the Moon moves on in splendor — R.T.H. Griffith (1896)
The oldest Indian reference to Ursa Major, and the only plural ṛkṣāḥ in the Ṛgveda (verified by exhaustive search of the Aufrecht text). Griffith renders it generically as 'constellations' and does NOT translate 'Bears' — the identification rests on etymology (ṛkṣa cognate with Greek ἄρκτος, Latin ursa) and on Macdonell & Keith, Vedic Index (1912) i.114: 'Rksa, "bear," is found only once in the Rigveda... Not more frequent is the use of the word in the plural to denote the "seven bears," later called the "seven Rsis," the constellation of the "Great Bear"', citing precisely RV 1.24.10, Śatapatha Brāhmaṇa 2.1.2.4, and Taittirīya Āraṇyaka 1.11.2.
Ṛgveda & Vedāṅga Jyotiṣa · c. 800–600 BCE
ऋषयः सप्तात्रिश्च यत् । सर्वेऽत्रयो अगस्त्यश्च । नक्षत्रैः शंकृतोऽवसन्, इति । अथ सवितुः श्यावाश्वस्यावर्तिकामस्य, इति । अमी य ऋक्षा निहितास उच्चा । नक्तं ददृश्रे कुहचिद्दिवेयुः । अदब्धानि वरुणस्य व्रतानि । विचाकशच्चन्द्रमा नक्षत्रमेति, इति ।
The seven Ṛṣis and Atri; all the Atris and Agastya; they dwelt blessed among the asterisms. — Then, of Savitṛ, of Śyāvāśva who desires... — Those Bears that are set on high, seen at night: whither by day have they gone? Unimpaired are Varuṇa's ordinances; surveying all, the moon goes to the asterism. — No public-domain English translation of the Taittirīya Āraṇyaka located; literal rendering supplied by the compiler
This is the passage that makes the Bear identification defensible. TĀ 1.11 names the Seven Ṛṣis, Atri and Agastya as dwelling 'with/among the nakṣatras' and then, in the very next breath, quotes the Ṛgvedic ṛkṣāḥ verse. It also transmits a significant variant: where RV 1.24.10 ends नक्तमेति ('goes by night'), the Āraṇyaka reads नक्षत्रमेति ('goes to the asterism'). Macdonell & Keith cite exactly this passage under their 'Rksa = Great Bear' entry.
Lexicons, Nirukta & Buddhist · Nirukta c. 5th century BCE; Amarakośa c. 6th century CE
ऋक्षा उदीर्णानीव ख्यायन्ते । स्तृभिस्तीर्णानीव ख्यायन्ते । अमी य ऋक्षा निहितास उच्चा । पश्यन्तो द्यामिव स्तृभिः । इत्यपि निगमौ भवतः ।
'Rkṣāh (stars) appear to be raised up. Strbhih (stars) appear to be scattered (in the sky). "These stars which are placed on high." "Looking at the sky with stars, as it were." These are two Vedic quotations.' — Lakshman Sarup (1921)
DECISIVE FOR THE BEAR CONTROVERSY, and against it. Yāska explains ṛkṣāḥ NOT from ṛkṣa 'bear' but as 'they appear as if raised up' (udīrṇāni iva khyāyante), and quotes exactly the verse RV 1.24.10 already on file. So the oldest Indian etymologist reads ṛkṣa as a general word for star, derived from height, and knows nothing of the Bear — a point directly against the Indo-European ṛkṣa/ἄρκτος/ursa equation. The Amarakośa confirms the flattening: by the 6th century ṛkṣa is a plain neuter synonym of nakṣatra, 'a star'.