SB 12.8.32
tasyaivam yuñjatas cittam
tapah-svadhyaya-samyamaih
anugrahayavirasin
nara-narayano harih
Translation:
Desiring to bestow His mercy upon the saintly Markandeya, who had perfectly fixed his mind in self-realization through penance, Vedic study and observance of regulative principles, the Supreme Personality of Godhead personally appeared before the sage in the forms of Nara and Narayana.