Why an Ark?
Why was it necessary for Noah to build an ark in order to save his family from the Flood's destruction? Could God not have arranged an easier way to rescue him? 
Could God not have arranged an easier way to rescue him?
The Midrash already raises this question, explaining that the 120 years that Noah worked constructing the enormous boat were meant to provide the people of his generation a chance to repent.
Rebuilding the World
Rabbi Moshe Chaim Luzzatto, the eighteenth-century scholar, gave an alternative explanation. He wrote that the year spent inside the ark was necessary to prepare the foundations for a new world. Outside the ark, where flood waters swept away the world's evil, nothing could survive. Inside the ark, the inner integrity of the world was reestablished under Noah's direction. The soul of this great tzaddik encompassed all the souls of the world. As Noah fed and looked after the animals in his care, he renewed the world on the basis of goodness and kindness.
A similar preparatory stage of spiritual renewal took place many years later. Before the revelation of the Zohar, Rabbi Shimon bar Yochai hid in a cave for thirteen years. He needed this period of seclusion to purify and prepare himself for the Zohar's inner light (Adir Bemarom 7).
The Path of Personal Growth
The same phenomenon is true, Rabbi Avraham Yitchak Kook wrote, for our own moral and spiritual growth. All change is difficult. It is hard to correct habits and rectify patterns of thought. As one becomes accustomed to view life in terms of materialistic desires, without thinking one is drawn to egotism and the pursuit of honor and physical pleasures.
The path to repair deeds and refine character traits has two aspects. The first pertains to the intellect. One must gain knowledge of each trait and its characteristics, to know the proper time and place for each trait. Thus, our very first request in the daily prayers is that God should "grant us knowledge, understanding and insight."
Theoretical knowledge, however, is not enough. Even after acquiring this wisdom, it is necessary to accustom the will and the corresponding physical powers so that they will wholeheartedly conform to this new path. One must strive to quiet the heart, distancing oneself from all that leads to a confused state, thus undermining the foundations of character-building. One needs to acquire a determined and steadfast outlook, to fortify one's traits so that they will retain their purity and holiness even when occupied in worldly matters.
A Private Ark
One who succeeds in directing his intellect and will in this fashion will rule over all aspects of life. But for one who has not thought out his path, his actions and desires are not under the control of the intellect. Such a person needs to withdraw the powers of the soul, gathering them in, like lines pulled back to their focal point. "He will gather in his spirit and soul to himself." (Job 34:14)
That undertaking is similar to Noah's confinement within the ark. It is a bitter and heavy burden, since the soul naturally desires freedom and expanse. Even confinement in the body is a terrible prison for the soul; all the more to be constrained in such a fashion.
Convergence to the nucleus of intellect and inner will is not a pleasant task. One will feel pained and even depressed from the constraints of this path of repair. But when the soul's forces have become accustomed to proper ways, they may be allowed to return to their natural state. Then, one's spirit and all aspects of the 
This path of personal renewal parallels the renewal of the world in the time of Noah.
personality will be proper vessels for fulfilling God's will, and one's powers may be freed to rule over the body, following the dictates of the intellect.
This path of personal renewal parallels the renewal of the world in the time of Noah. The months spent in the ark were a preparatory period of converging and gathering powers, under the direction of the tzaddik. But when the inhabitable dry land appeared, as the punishing waters receded, Noah and the inhabitants could once again be free of their confinement. So, too, as the character traits are repaired and perfected, they may be released once again.
Testing the Waters
During the period of confinement, one needs to 'test the waters' - to measure whether one's powers are ready to be set free. This stage corresponds to Noah's sending out the raven and the dove. One tests one's traits in matters that do not involve danger, just like the birds were not endangered by the flood waters. When the tzaddik realized that the world's repair was still unfinished, he withdrew them back into the ark.
Only when the land was completely dry came the Divine command, "Leave the ark!" Then it was time to serve God in a free and unhindered manner, for the spread of Torah and kindness requires a courageous soul, full of strength, in order to advance freely.
[Adapted from Mussar Avicha pp. 33-39]