SB 3.8.13
tasyartha-suksmabhinivista-drster
antar-gato ’rtho rajasa taniyan
gunena kalanugatena viddhah
susyams tadabhidyata nabhi-desat
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The subtle subject matter of creation, on which the Lord’s attention was fixed, was agitated by the material mode of passion, and thus the subtle form of creation pierced through His abdomen.