Matsyapurana 144.94

144.94

saha saptarṣibhirye tu tatra ye ca vyavasthitāḥ
brahmakṣatraviśaḥ śūdrā bījārthe ya iha smṛtāḥ
kārtayugabhavaiḥ sārdhaṃ nirviśeṣāstadābhavan //

When the Satyayuga comes in its people are procreated by those who remained at the end of Kaliyuga The good and perfect persons that remained unnoticed amongst the Brâhmanas Ksatriyas, Vaisyas and Sûdras they and the Saptarṣis now give instructions in dharma to the new people In that way the doctrines of the Risis based on Śrutis and Smṛitis are propagated They promulgated Varnâsrama Dharma and other rituals on the lines of Śrutis and Smṛitis The Saptarṣis hold the dharma of the Śrutis and Smritis For promulgating dharma the Saptarṣis are ever ready in every Satyayuga These Risis are now existing for the period of one Manvantara As the roots of plants and trees vigorously germinate after being consumed by fire, similarly, there is a growth in the generation of people at the commencement of the Satya age. In this way, generations of the ages go on for ever The ideas appear and disappear. Comforts, life power, beauty, dharma, Artha and Kāma lose onefourth their quantity in every Yuga—92-100