Aseity means that God is self-existent and self-sufficient. He exists in and of Himself, is independent of His creation and is complete in Himself. He is not served by human hands as though He needed anything; He gives life and breath to all, and in Him we live and move and exist. By contrast, the creation is totally dependent, first on God as Creator and Sustainer and then on fellow creatures.
The lesson warns against the idea that God created us because He was lonely or needed an outlet for His love. That makes God dependent on His creation and denies His aseity. The world and everything in it already belong to Him, and the nations are as nothing before Him. The study closes with the question of what the God who made us wants from us, and answers from Isaiah: the one who is humble and contrite in spirit and trembles at His word.