"By faith Noah, being warned of God of things not seen as yet, moved with fear, prepared an ark to the saving of his house; by the which he condemned the world, and became heir of the righteousness which is by faith" (Hebrews 11:7).
Noah was indeed a man of mighty faith, believing God's Word even about "things not seen as yet," preparing for a worldwide Flood in a day when God had never yet even "caused it to rain upon the earth" (Genesis 2:5). Noah was "a preacher of righteousness" (II Peter 2:5) to an unbelieving world for at least 120 years (Genesis 6:3), "while the ark was a preparing" (I Peter 3:20), without gaining any converts except his own family.
But why would he have been "moved with fear"? Noah was surely not afraid to die! He had "walked with God" (Genesis 6:9) for 600 years (5:32; 7:11) before the Flood, and he was certainly not afraid to die and go to meet the Lord now.
Evidently it was for "the saving of his house" that he was afraid, realizing that his own children would soon be engulfed by the awful spirit of unbelief and wickedness that pervaded the antediluvian world, if they could not somehow be delivered from it. So he "prepared an ark," and his house was saved. "Come thou and all thy house into the ark," said the Lord, "for thee have I seen righteous before me in this generation" (7:1). Although they could easily have refused, they all chose to follow Noah.
In like manner today, God speaks to the head of each house: "Believe on the Lord Jesus Christ, and thou shalt be saved, and thy house" (Acts 16:31). A consistent example of obedient faith set by a godly father (or mother, if necessary) almost inevitably results in his (or her) children also trusting in the Lord for salvation. Every caring parent should resolve that, "as for me and my house, we will serve the LORD" (Joshua 24:15). HMM