योगवासिष्ठः yogavāsiṣṭhaḥ - book-2, chapter-13, verse-29

परस्परविनाशोक्तेः श्रेयःस्थो न कदाचन ।
सुखदुःखदशे राम तडित्प्रसरभङ्गुरे ॥ २९ ॥

parasparavināśokteḥ śreyaḥstho na kadācana ,
sukhaduḥkhadaśe rāma taḍitprasarabhaṅgure 29

29. parasparavināśokteḥ śreyassthaḥ na kadācana
sukhaduḥkhadaśe rāma taḍitprasarabhaṅgure

29. rāma,
parasparavināśokteḥ śreyassthaḥ kadācana na.
sukhaduḥkhadaśe taḍitprasarabhaṅgure.

29. O Rama, due to the pronouncements of mutual destruction, no one is ever established in well-being (śreyas). The twin states of happiness and sorrow are fleeting like the flash of lightning.

Words meanings summery:

• परस्परविनाशोक्तेः (parasparavināśokteḥ) - owing to the statement or belief in each other's destruction (from the declaration of mutual destruction, due to the talk of reciprocal ruin)

• श्रेयस्स्थः (śreyassthaḥ) - a person who enjoys or attains ultimate good (śreyas) (one established in well-being, standing in good fortune)

• न (na) - negation (not, no)

• कदाचन (kadācana) - 'never' when combined with 'na' (ever, at any time, never (with na))

• सुखदुःखदशे (sukhaduḥkhadaśe) - the dual conditions of pleasure and suffering (O states of happiness and sorrow, the two states of joy and pain)

• राम (rāma) - Address to Rama (O Rama)

• तडित्प्रसरभङ्गुरे (taḍitprasarabhaṅgure) - ephemeral, quickly vanishing like a lightning strike (transient like the flash/spread of lightning)

Words meanings and morphology

परस्परविनाशोक्तेः (parasparavināśokteḥ) - owing to the statement or belief in each other's destruction (from the declaration of mutual destruction, due to the talk of reciprocal ruin)

(noun)

Ablative, feminine, singular of parasparavināśokti

parasparavināśokti - declaration of mutual destruction

Compound type : tatpuruṣa (paraspara+vināśa+ukti)

• paraspara – mutual, reciprocal, each other
  indeclinable
• vināśa – destruction, ruin, annihilation
  noun (masculine)
  from vi-naś 'to perish'
  Prefix: vi
  Root: naś (class 4)
• ukti – speech, declaration, statement
  noun (feminine)
  from root vac 'to speak'
  Root: vac (class 2)

Note: Acts as 'because of' or 'from'.

श्रेयस्स्थः (śreyassthaḥ) - a person who enjoys or attains ultimate good (śreyas) (one established in well-being, standing in good fortune)

(adjective)

Nominative, masculine, singular of śreyasstha

śreyasstha - established in well-being (śreyas), standing in good fortune

Compound type : tatpuruṣa (śreyas+stha)

• śreyas – well-being, excellence, ultimate good, welfare
  noun (neuter)
• stha – standing, existing, abiding in
  adjective (masculine)
  from root sthā 'to stand'
  Root: sthā (class 1)

Note: Used substantively.

न (na) - negation (not, no)

(indeclinable)

कदाचन (kadācana) - 'never' when combined with 'na' (ever, at any time, never (with na))

(indeclinable)

सुखदुःखदशे (sukhaduḥkhadaśe) - the dual conditions of pleasure and suffering (O states of happiness and sorrow, the two states of joy and pain)

(noun)

Vocative, feminine, dual of sukhaduḥkhadaśā

sukhaduḥkhadaśā - state of happiness and sorrow

Compound type : dvandva-tatpuruṣa (sukha+duḥkha+daśā)

• sukha – happiness, joy, pleasure
  noun (neuter)
• duḥkha – sorrow, suffering, pain, misery
  noun (neuter)
• daśā – state, condition, period, circumstance
  noun (feminine)

Note: Refers to the two states (happiness and sorrow).

राम (rāma) - Address to Rama (O Rama)

(proper noun)

Vocative, masculine, singular of rāma

rāma - Rama (proper name of a Hindu deity), pleasing, charming

तडित्प्रसरभङ्गुरे (taḍitprasarabhaṅgure) - ephemeral, quickly vanishing like a lightning strike (transient like the flash/spread of lightning)

(adjective)

Vocative, feminine, dual of taḍitprasarabhaṅgura

taḍitprasarabhaṅgura - perishable like the flash of lightning

Compound type : tatpuruṣa-bahuvrīhi (taḍit+prasara+bhaṅgura)

• taḍit – lightning, flash of lightning
  noun (feminine)
• prasara – spread, extension, flow
  noun (masculine)
  from pra-sṛ 'to spread'
  Prefix: pra
  Root: sṛ (class 1)
• bhaṅgura – perishable, fragile, transient
  adjective (masculine)
  from root bhañj 'to break'
  Root: bhañj (class 7)

Note: Agrees with sukhaduḥkhadaśe.