सर्गादिषु पृथग्विभूतयश्चतस्रः आत्मनः यस्य सः चतुरात्मा ।
In plain words
In creation and the rest, his one self stands forth as four distinct powers, each apart from the others. That is why he is called Caturātmā — the one whose self is fourfold.
Close to the Sanskrit
He of whom, in creation and the rest, there are four separate manifestations of the self — he is Caturātmā.