Garudapurana 3.10.41

3.10.41

tattvānāṃ bahugopyatvāttathoktaṃ brahmaṇā purā /
abhiprāyastvevameva jñātavyo nātra saṃśayaḥ //

Because principles must be kept very secret, it was spoken in that way by Brahmā of old. / The intention should be understood in just this way; there is no doubt here.