महाभारतः mahābhārataḥ - book-3, chapter-216, verse-15

तस्याभयं ददौ स्कन्दः सहसैन्यस्य सत्तम ।
ततः प्रहृष्टास्त्रिदशा वादित्राण्यभ्यवादयन् ॥१५॥

15. tasyābhayaṁ dadau skandaḥ sahasainyasya sattama ,
tataḥ prahṛṣṭāstridaśā vāditrāṇyabhyavādayan.

15. tasya abhayam dadau skandaḥ sahasainyasya sattama
tataḥ prahṛṣṭāḥ tridaśāḥ vāditrāṇi abhyavādayan

15. Skanda, O best of beings, granted fearlessness (abhaya) to Indra, along with his army. Then, the greatly delighted thirty gods (tridaśa) played their musical instruments.

Words meanings summery:

• तस्य (tasya) - to him (Indra) (to him, of him)

• अभयम् (abhayam) - fearlessness, safety, security

• ददौ (dadau) - gave, granted

• स्कन्दः (skandaḥ) - Skanda

• सहसैन्यस्य (sahasainyasya) - of Indra, who was accompanied by his army (of him with his army, along with his army)

• सत्तम (sattama) - O best of beings (vocative)

• ततः (tataḥ) - then, therefrom, afterwards

• प्रहृष्टाः (prahṛṣṭāḥ) - greatly delighted, overjoyed

• त्रिदशाः (tridaśāḥ) - the thirty gods, deities

• वादित्राणि (vāditrāṇi) - musical instruments

• अभ्यवादयन् (abhyavādayan) - played (instruments)

Words meanings and morphology

तस्य (tasya) - to him (Indra) (to him, of him)

(pronoun)

Dative, masculine, singular of tad

tad - that, he, she, it

Note: Here it's dative with dā (to give).

अभयम् (abhayam) - fearlessness, safety, security

(noun)

Accusative, neuter, singular of abhaya

abhaya - fearlessness, safety, security, freedom from fear

Compound type : nañ-tatpuruṣa (a+bhaya)

• a – not, non-
  indeclinable
  Negative prefix
• bhaya – fear, dread
  noun (neuter)
  Root: bhī (class 3)

ददौ (dadau) - gave, granted

(verb)

3rd person , singular, active, past perfect (lit) of dā

Perfect

Root verb, perfect active, 3rd person singular.

Root: dā (class 3)

स्कन्दः (skandaḥ) - Skanda

(proper noun)

Nominative, masculine, singular of skanda

skanda - Skanda, Kartikeya, the god of war

सहसैन्यस्य (sahasainyasya) - of Indra, who was accompanied by his army (of him with his army, along with his army)

(adjective)

Genitive, masculine, singular of sahasainya

sahasainya - along with the army, accompanied by the army

Bahuvrihi compound: "one who has an army with him". Formed from saha (with) and sainya (army).

Compound type : bahuvrīhi (saha+sainya)

• saha – with, together with
  indeclinable
• sainya – army, troops
  noun (neuter)
  Root: senā

Note: Agrees with tasya (Indra).

सत्तम (sattama) - O best of beings (vocative)

(adjective)

Vocative, masculine, singular of sattama

sattama - best of good men, best of beings

Superlative of sat (good, existing).

Root: as

Note: Addressed to the listener/reader.

ततः (tataḥ) - then, therefrom, afterwards

(indeclinable)

प्रहृष्टाः (prahṛṣṭāḥ) - greatly delighted, overjoyed

(adjective)

Nominative, masculine, plural of prahṛṣṭa

prahṛṣṭa - greatly delighted, overjoyed, excited

Past Passive Participle-like

Derived from root hṛṣ with upasarga pra.

Prefix: pra

Root: hṛṣ (class 4)

त्रिदशाः (tridaśāḥ) - the thirty gods, deities

(noun)

Nominative, masculine, plural of tridaśa

tridaśa - the thirty (gods), deities

Compound type : dvigu (tri+daśa)

• tri – three
  numeral
• daśa – ten
  numeral

वादित्राणि (vāditrāṇi) - musical instruments

(noun)

Accusative, neuter, plural of vāditra

vāditra - musical instrument, instrument for playing music

Derived from root vad (to speak, play an instrument).

Root: vad (class 1)

अभ्यवादयन् (abhyavādayan) - played (instruments)

(verb)

3rd person , plural, active, past imperfect (laṅ) of vad

Imperfect (causative)

Causative of root vad, imperfect active, 3rd person plural.

Prefixes: abhi+ava

Root: vad (class 1)