In the Middle Persian commentaries of the 9th-12th centuries, the divinity appears as S(a)rosh. This form appears in many variants in New Persian as well, for example Perso-Arabic سروش, Sorūsh. Unlike many of the other Yazatas (concepts that are "worthy of worship"), Sraosha has no Vedic equivalent.
Sraosha is also frequently referred to as the "Voice of Conscience", which overlaps with both "Obedience" and as his role as the "Teacher of Daena", Daena being the hypostasis of both "Conscience" and "Religion".
In the Gathas, Sraosha's primary function is to propagate the religion of Ahura Mazda to humanity, as Sraosha himself learned it from Mazda. This is only obliquely alluded to in these old verses but is only properly developed in later texts (Yasna 57.24, Yasht 11.14 etc). Directly evident in the Gathas is the description as the strongest, the sturdiest, the most active, the swiftest, and the most awe-inspiring of youths (Yasna 51.13), and as the figure that the poor look to for support (51.10).
In the ethical goals of Zoroastrianism ("good thoughts, good words, good deeds") as expressed in Yasna 33.14, Sraosha is identified with good deeds. This changes in Zoroastrian tradition (Denkard 3.13-14), where Sraosha is identified with good words.
In Yasna 56-57, Sraosha is variously described as mighty, the incarnate word of reason, whose body is the holy spell (57.1). He "possesses Truth" (ashavanem) and is "stately" (57.2, 57.5, 57.7, 57.9, 57.11, 57.15 etc). He is said to have been the first in all of creation to worship Ahura Mazda and the Amesha Spentas. (57.2 and 57.6). He recited five holy verses in order to favour the great sextet (57.8), and the Ahuna Vairya invocation and other sacred formulae are his weapons (57.22). He returned victorious from his battles with evil (57.12), which allowed the various aspects of creation to populate the world (57.23). Sraosha wanders about the world teaching the religion of Mazda (57.24). Sraosha is frequently described as the "lord of ritual" (57.2, 57.5, 57.7, 57.9, 57.11 etc) and he propitiates Haoma with sacrifice (57.19).
In Yasht 11, mankind lives under Sraosha's constant guardianship (11.7). He is not interrupted by sleep in his constant vigil (11.14) in which he wields his weapons against the druj (11.0). Sraosha teaches the word of Ahura Mazda to mankind (11.14). The poor look to him for support (11.3) and he is welcome in all homes that he protects (11.20).
In yet other texts Sraosha is again protector of ritual, but here the celebrant priest receives the epithet Sraoshavarez (Yasht 24.15; Vendidad 5.25, 7.17 et al). In Vendidad 18.22, Sraosha is called for help against the demon-serpent Azi Dahaka who threatens to extinguish the hearth fire (cf. Atar).
Sraosha is the chief adversary of Aeshma, the demon (daeva) of "wrath," for Aeshma distracts from proper worship, distorting "the intention and meaning of sacrifice through brutality against cattle and violence in war and drunkenness." While Aeshma's standard epithet is xrvi.dru- "of the bloody mace," Sraosha's standard epithet is darshi.dru- "of the strong (Ahuric) mace." Sraosha will overthrow Aeshma at the renovation of the world (Yasht 19.95).
As also the other two guardians of the bridge, Sraosha is closely identified with Ashi, "Recompense". In Yasht 17.15 and 17.17, Sraosha is called Ashi's "brother." One of Sraosha's stock epithets is ashya, which may either mean "companion of recompense" or simply "companion of Ashi".
In the day-name dedications of the Zoroastrian calendar, the seventeenth day of the month is dedicated to Sraosha.