Lord Buddha directed the monks to have self (Atta) as refuge (Dipa) and shelter (Sarana) and dhamma as refuge and shelter, "Monks, you must be one who has self as refuge, self as shelter, nothing else as shelter. You must be one who has dhamma as refuge, dhamma as shelter, nothing else as shelter" (D. 49/84).
The question arises whether “self” in this statement refers to conventional, worldly self (person, we-they, us-them) or self in the ultimate sense, (the Supra-mundane Nirvana Element) or to both. The commentary says that “self” in this statement refers to both worldly and Supra-mundane dhammas as follows, "What is called self in Attadipa? Change to worldly dhammas and Supra-mundane dhammas [are called self]" (DA, 3/30).
Moreover, the sub-commentary explains that the nine Supra-mundane dhammas are self and a refuge like an island (the ultimate Nirvana), "The self as Attadipa that the Lord refers to, in this context, are dhammas. Lord Buddha has previously stated they are the nine Supra-mundane dhammas. Lord Buddha calls the nine Supra-mundane dham-mas [including Nirvana] islands because they are not flooded by the four waters of sensual desire (Kama), becoming or existing (Bhava), wrong view (Ditthi) and ignorance (Avijja)" (SA, 2/557).