Why did Justin come back to life after his death?

In The Romance of the Gods, Justin will not be killed, because he is protected by Gong Xuan in 1989. When Yang Jian cut off Justin's head with a knife, a Bai Lianhua was soon born around Justin's neck, and then Bai Lianhua became Justin's head. In order to execute Justin, Jiang Ziya took out the immortal flying knife that Taoist Liuya gave him. Seven inches and five minutes, the eyebrow-shaped fairy flew a knife and shot two white lights to crucify Justin, followed by Jiang Ziya respectfully saying "Please turn around", and then Justin, who was beheaded, never came back to life.