In Hinduism God is considered as both Sakara (with form) and Nirakara (without form). So, Saguna worship and Nirguna worship both are prescribed.
For example, this question quotes a verse from the Brihad Aranyaka Upanishad, which clarifies that God is Amurta (without a form/murti) and at the same time Murta (with a form).
dve vāva brahmaṇo rūpe, mūrtaṃ ...
Yes, there are a few instances in both Taittirīya Saṃhitā and Brāhmaṇa (attached to Kṛṣṇa Yajurveda) and the Śatapatha Brāhmaṇa (Śukla Yajurveda) where it's said śūdras are not fit to conduct yajñas and that brāhmaṇas and kṣatriyas are superior to other varṇas (vaiśyas and śūdras).
Taittirīya Saṃhitā (Kṛṣṇa Yajurveda) on śūdras:
The other answer has the shloka attributed to Acharya Sayana. Sayana quotes it in two places - Once while commenting on Rig Veda 1.50.4 and again while commenting on Rig Veda 1.71.9. At both places Rig Veda mentions that movement for Surya is very fast. To establish that Surya indeed moves fast he quotes this verse.
It should be noted that whenever ...
The seer (rishi) is Visvedevas (Viśvedevāḥ) according to this Krishna-yajurveda Taittiriya Samhita published by Svadhyaya Mandal, Pune in 1957.
The screenshot below is from the Kanda 4, Prapathaka 4, Anuvaka 12. The Nila Sukta starts with gṛṇāhi | ghṛtavatī. Viśvedevāḥ is the seer for entire 4.4.12.