The Story of Noah and the Ark /p4
So Noah opened the door of the ark, and with his family came out, and stood once more on the ground. And the animals, and birds, and creeping things in the ark, came out also, and began again to bring life to the earth.
The first thing that Noah did when he came out of the ark, was to give thanks to God for saving all his family when the rest of the people on the earth were destroyed. He built an altar, and laid upon it an offering to the Lord, and gave himself and his family to God and promised to do God's will.
And God was pleased with Noah's offering, and God said:
"I will not again destroy the earth on account of men, no matter how bad they may be. From this time no flood shall again cover the earth; but the seasons of spring and summer and fall and winter, shall remain without change. I give to you the earth; you shall be the rulers of the ground and of every living thing upon it."
Then God caused a rainbow to appear in the sky, and he told Noah and his sons that whenever they or the people after them should see the rainbow, they should remember that God had placed it in the sky and over the clouds as a sign of his promise, that he would always remember the earth, and the people upon it, and would never again send a flood to destroy man from the earth.
So as often as we see the beautiful rainbow, we are to remember that it is the sign of God's promise to the world.