In speaking about the time of Noah, the Bible explains, "every inclination of the thoughts of man's heart was only bad all the time" and the earth became "ruined, because all flesh had ruined its way on the earth." -Gen 6:5, 11, 12.
From the time that gross wickedness began, God set a time when he would bring an end to the wickedness on earth, 120 years according to Gen 6:3. In setting a specific time, Jehovah took into consideration more than the destruction of the wicked. Jehovah's timetable provided for the preservation of the righteous.
Noah avoided the world's corruption and is described by God's word as a righteous man.
Noah proved himself faultless amoung his contemporaries.
Noah walked with the true God.- Gen 6:8,9
Jehovah gave detailed information to Noah, to build an ark "for the saving of his household" Compare: Gen 6:13, 14, 18, 19
Consider this assignment from Noah's viewpoint. Noah understood that before God would destroy the ungodly, there was work to be done-a work that would require faith. The construction of the ark would be a colossal project. The dimensions God gave, meant the ark would be longer than some modern-day sports fields and as high as a five-story building. (Gen 6:15) On top of that, the builders, Noah and his sons, were inexperienced and few. They would not have the tools and equipment we have today. No lumber yards, no hardware stores! And this work would not be in secret, Noah would explain to his neighbors why he using his time, yes, his life to build this ark. They no doubt would oppose him.
Jehovah assured Noah that he and his family would enter a completed ark and be preserved alive through the global Flood. God even underscored the certainty of that with a solemn promise and brought Noah into a covenant agreement with Him. -Gen 6:18,19.
So with full confidence, "that what God had promised he was also able to do" Noah assisted by his family, set to work on this huge God-given assignment. As the years passed, the ark took shape. Construction problems were resolved. Trials were overcome. No opposition could halt the work. Noah's family experienced Jehovah's support and protection. Their faith was fortified. As Noah pressed on, 'the tested quality of his faith worked out endurance' (Compare James 1:2-4) Noah did "according to all that God had commanded. He did just so". -Gen 6:22.
Finally, the ark was completed, the Flood came, Noah and his family survived. Noah experienced the fulfillment of God's promises. We too are blessed from Noah's faith in action. Not only was human and animal life allowed to continue on the earth, but through Noah, true worship was also preserved, along with the history of creation. For this we may be thankful.