He received a message from God (Genesis 6:11–21; Genesis 6:22 mentions the obedience of Noah). The same word is used in Hebrews 8:5 concerning the instruction that God gave to Moses about the tent of worship. And Noah, in reverent fear, constructed an ark (Hebrews 11:7). He began building on dry land without a flood in sight. But Noah did not start to criticize or question God. He had reverence for the Lord; the NIV translates it as holy fear.
The same word is used in Hebrews 5:7 when Jesus offered up prayers and supplications, with loud cries and tears, [in Gethsemane] to him who was able to save him from death, and he was heard because of his reverence.
Reverence is the attitude of the righteous one.
7 By faith Noah, being warned by God concerning events as yet unseen, in reverent fear constructed an ark for the saving of his household. By this he condemned the world and became an heir of the righteousness that comes by faith.