prakṛti--kāraṇa yaiche ajā-gala-stana
ataeva-therefore; kṛṣṇa-Lord Kṛṣṇa; mūla-original; jagat-kāraṇa-the cause of the cosmic manifestation; prakṛti-material nature; kāraṇa-cause; yaiche-exactly like; ajā-gala-stana-nipples on the neck of a goat.
Therefore Lord Kṛṣṇa is the original cause of the cosmic manifestation. Prakṛti is like the nipples on the neck of a goat, for they cannot give any milk.
"Although smoke, flaming wood, and sparks are all considered together as ingredients of a fire, the flaming wood is nevertheless different from the fire, and the smoke is different from the flaming wood." The material elements (earth, water, fire, etc.) are like smoke, the living entities are like sparks, and material nature as pradhāna is like the flaming wood. But all of them together are recipients of power from the Supreme Personality of Godhead and are thus able to manifest their individual capacities. In other words, the Supreme Personality of Godhead is the origin of all manifestations. Material nature can supply only when it is activated by the glance of the Supreme Personality of Godhead.