What is the interpretation of verse 11 from Surat Fussilat: (Then He directed Himself to the heaven while it was smoke and said to it and to the earth, “Come [into being] willingly or unwillingly.” They both said, “We have come willingly”)?

The creation of the Earth took two days. Then, Allah placed firm mountains therein, blessed it, and ordained its provisions in two additional days. Then He directed Himself to the heaven while it was smoke, and He completed them as seven heavens in two days, and He revealed in each heaven its affair. And We adorned the nearest heaven with lamps and as protection. So, the total number of days is six. "He directed Himself to the heaven" means He intended to create it. "Smoke" refers to water vapor. And His saying, "Come willingly or unwillingly," means to submit to My command.