विधूतकलुषैः सिद्धैस्तपोदमशमान्वितैः।
नित्यविक्षोभितजलां विगाहस्व मया सह॥
vidhūta-kaluṣaiḥ siddhais tapo-dama-śamānvitaiḥ
nitya-vikṣobhita-jalāṁ vigāhasva mayā saha
vidhūta-kaluṣaiḥ = and who are therefore cleansed of all internal contamination; siddhaiḥ tapaḥ-dama-śama-anvitaiḥ = by those fixed on attaining the perfection of their spiritual practices; nitya-vikṣobhita-jalām = her waters are regularly agitated; vigāhasva = immerse into this river; mayā saha = with Me.
Immerse into this river with Me. Her waters are regularly agitated by those fixed on attaining the perfection of their spiritual practices and who are therefore cleansed of all internal contamination.
1 Rāmāyaṇa-bhūṣaṇa: mayā saha vigāhasva mām apradhānīkṛtya jala-krīḍā-rasam anubhavety arthaḥ.
“Cleansed of all internal contamination” indicates that the sages who regularly bathed in Mandākinī had become free of sinful contamination and that they had blessed her with the dust of their feet.
Mayā saha (“with Me”) indicates that Rāma wanted Sītā-devī to enjoy the mellows of water sports in His company.1 [And] that the river was regularly agitated indicates that saffron and similar items [needed for water sports] were already in [the water].