Genesis 6:15 gives the measurements God told Noah to use when building the ark: 300 cubits long, 50 cubits wide, and 30 cubits high. The verse is a set of construction specifications, showing that the rescue God planned was built to a precise design rather than left to guesswork. God speaks these words to Noah in the days before the flood, as part of the instructions for the vessel that would carry Noah’s family and the animals through the waters.
This is how you shall make it. The length of the ship shall be three hundred cubits, its width fifty cubits, and its height thirty cubits.
Genesis 6:15 (WEB)
What Genesis 6:15 Means
The verse opens with “This is how you shall make it,” which tells Noah that the instructions that follow are a blueprint to be followed closely. God is not describing a vague shelter. He is giving a plan, and the plan is the first thing Noah needs to trust.
The three measurements, length, width and height, give the ark its shape. Three hundred cubits long is roughly 450 feet by ancient reckoning, a very large wooden vessel for its time, while fifty cubits wide and thirty high give it a low, broad hull that would have floated stably. The proportions suggest a boat built to stay afloat for a long voyage, not to race across open water.
What the verse does not do is explain why these exact dimensions were chosen or describe how the ark would be sealed and fitted inside. Those details come in the surrounding verses. Genesis 6:15 promises nothing about the outcome of the flood itself. It simply shows that God gave Noah a clear, workable plan for survival.
The Context of Genesis 6:15
Genesis is the first book of the Torah, traditionally attributed to Moses, and it opens the larger story of God’s dealings with humanity and the covenant people. Chapter 6 begins by describing how wickedness had spread across the earth, and verses 12 and 13 explain that God saw the corruption and violence and resolved to bring it to an end. Noah stands out because he walked faithfully with God, and this passage is where God first lays out his plan to preserve a remnant through him.
Read in that setting, Genesis 6:15 is part of a rescue, not just a building project. Verse 14 tells Noah to make the ship of gopher wood and seal it with pitch, and verses 16 through 18 describe the roof, the door, the levels and God’s covenant promise to Noah and his family. The measurements in verse 15 sit at the center of a passage about judgment and mercy together, which means the ark is a sign of God’s careful provision in the middle of a warning.
Key Phrases in Genesis 6:15
Hebrews 11:7
By faith, Noah, being warned about things not yet seen, moved with godly fear, prepared a ship for the saving of his house, through which he condemned the world, and became heir of the righteousness which is according to faith.
(WEB)
This verse names Noah’s response to God’s warning as faith, moving with reverence to build the ark. It shows the same pattern found in Genesis 6:15: God gives a clear direction, and Noah’s obedience becomes the visible expression of his trust.
Genesis 7:16
Those who went in, went in male and female of all flesh, as God commanded him; then the LORD shut him in.
(WEB)
Here the narrative moves from the building to the boarding, and the verse notes that the Lord himself shut Noah in. It connects to the construction instructions by showing that the ark, built to God’s specifications, also rested under God’s protection once the family entered it.
A Short Prayer From Genesis 6:15
Lord, you gave Noah a clear plan when the world around him had gone wrong, and you asked him to follow it with care. Help me to trust your instructions in the details of my life, even when I cannot see the whole picture. Where I am tempted to rush ahead or to cut corners, slow my heart and steady my hands. Let my obedience be shaped by faith in you, the God who keeps his promises. Amen.
