Garudapurana 3.3.47

3.3.47

yo vā tvaṇīyānparamasya viṣṇoḥ sa eva rūpo mahato mahīyān /
teṣāmanyonyaṃ na viśeṣosti kaścidacintyarūpe ca vicintanīyaḥ //

And that form of the supreme Viṣṇu which is subtler than the subtlest, that very one is greater than the greatest. / Between them there is no difference whatsoever; He is to be contemplated in His inconceivable form.