Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 8 · Marriage
विवाहः
कुजोऽष्टमो महादोषो लग्नादष्टमगे कुजे ।शुभत्रययुतं लग्नं न त्यजेत्तुंगगो यदि ॥ ४४६ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 446.
Mars in the 8th is a great fault, when Mars is in the 8th from the lagna (rising sign). A lagna joined by three good planets is not dropped if Mars is in his uchcha (high point).
Simple meaning: Mars in the 8th spoils a lagna, unless Mars is high and three good planets join the lagna.
पूर्णानंदाख्ययोस्तिथ्योः संधिर्नाडीद्वयं यदा ।
The meeting of Purna and Nanda moon days, two ghatikas long, is a risky junction for birth and marriage.
कुलीरसिंहयोः कीटचापयोर्मीनमेषयोः ।
The gap between those pairs of signs is a risky junction for half a ghatika.
सार्पैन्द्रपौष्णभेष्वंत्यषोडशेशा भसंधयः ।
The ends of Ashlesha, Jyeshtha and Revati and the starts of Magha, Mula and Ashvini are danger junctions.