teṅho - He; ta' - certainly; caitanya-kṛṣṇa - Kṛṣṇa with the name of Śrī Caitanya; śacīra nandana - the son of Śacīmātā; tṛtīya paricchede - in the Third Chapter; janmera - of His birth; sāmānya - general; kāraṇa - reason.

Śrī Kṛṣṇa Caitanya Mahāprabhu, who is Kṛṣṇa Himself, has now appeared as the son of mother Śacī. The third chapter describes the general cause of His appearance.