I am the beginning, the end and the middle of creations, oh Arjuna; of sciences I am the spiritual science; and of arguers I am the conclusive debate.

Sargāṇām — of creations/manifestations — the Lord is the entire process: ādiḥ (creation), madhyam (maintenance), antaḥ (dissolution).

Vidyānām — of sciences — adhyātma-vidyā — knowledge of the ātman, the highest. Pravadatām — of those who argue — vādaḥ — logical debate, especially that which establishes the truth of the ātman.

The Lord is the alpha and omega of all existence.