The Bible speaks to God's intention for men and women to "be fruitful and multiply" in several key verses, particularly in the context of creation and God's blessings on humanity. Here are the most relevant passages in the King James Version (KJV):

Genesis 1:27-28 "So God created man in his own image, in the image of God created he him; male and female created he them. And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth." This is the foundational verse where God commands humanity to procreate and steward creation.
Genesis 9:1 "And God blessed Noah and his sons, and said unto them, Be fruitful, and multiply, and replenish the earth." After the flood, God reaffirms His command to Noah and his family to repopulate the earth.
Genesis 2:24 "Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh." While this verse does not explicitly mention being fruitful, it establishes the union of man and woman as a foundation for family and procreation.
These verses reflect God’s design for human relationships, the continuation of life, and the stewardship of His creation through the partnership of men and women.