Yes, the title of the book is based on a quote from the book; however it seems to have greater significance in the scheme of things as it seems to bring so many thoughts and ideas from the novel to a close. During a huge party, a hurricane starts and begins to break up the party due to its severity. Tea Cake and Motor Boat stop what they are doing when they hear thunder outside, and Janie tells them to be quiet because “Ol’ Massa is doin’ His work now.” The noise of the storm makes the noises that they made at the party seem quite small by comparison. The implication is that this natural phenomenon is the product of God, which is instantly more impressive than anything that could be made by man. This storm can be a metaphor for the power of nature, the type of nature that we first read about in Janie’s gentle bee. It is as if they understand the power of God for the first time. When the winds knock out the power, the others wonder if “He meant to measure their puny might against His.” “Their eyes were watching God” in recognition of God’s power, and the farmers understand with whom true power lies. This power is symbolized by the lake. The strength of the rushing water can knock any one person aside easily, and this illustrates the power that God and nature possess over human beings.
The title comes from a quote in the book which reads, in full:
They seemed to be staring at the dark, but their eyes were watching God
It basically means that, you couldn't always tell, but people in the book have an emotional and ever-present knowledge and association with God.
The title symbolizes the lack of absolute control in life; everything is controlled by God. He is all-knowing. Throughout the story certain characters all desire control and create illusions for themselves, for example, Jody Starks. He only asks Janie marry him because she fits the criteria for a perfect and easy to control wife. He forces her to hide her hair, a symbol of her identity and independance, and bosses her around. Later on when Janie musters the courage to speak up, he dies because he realizes he has no control over her anymore. You can also argue that the community creates an illusion of control by not breaking away from tradition. In the beginning of the novel and also when Janie goes on dates with Tea Cake, the community looks down upon Janie's defiance of their morals. They don't like breaking away from tradition because they don't like change. If society remains the same then they already know what the future will be; everything will be exactly the same! This belief provides them with an illusion of control until it is obviously wronged by Janie, herself. Also, the hurricane proves that humans are not in control when it destroys the towns and kills several people. The storm serves as somewhat of an epiphany for the people. Their eyes are watching God helplessly as they realize His great power. They realize things may or may not go their way and this is shown by Tea Cake's death. Janie can't prevent him from dying after the hurricane.
It's important to note that the title is "their eyes" and not "her eyes." Although the story focuses on Janie the meaning of the title is more all-inclusive of humankind. There is a strong subtheme in the story of community (porch-sitters, mule-talkers) and what can happen if a person goes "against" community (for example, not listening to the Indians about the impending storm).
They were watching and waiting for the flood to come. God is nature, the source of the hurricane.
Their Eyes Where Watching God: the line appears in the book a couple of times near the end. Janie tells Pheoby “two things everybody got tuh do fuh theyselves. They got tuh go tuh God, and they got tuh find out about livin' fuh theyselves. Janie believes in God and that he will help you in time of need but not all the time. Her eyes were watching God to help Tea Cake make it through and not die. But Tea Cake did die. The people watching God are waiting helplessly for him but sometimes you have to take charge for yourself. Also, if you don’t take advantage of the signs God does give (the Indians warning Janie before the Hurricane) you then you really are on your own.