"But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die" (Genesis 2:17).
Adam should have given more careful consideration to God's solemn warning of the consequences of sin.  God said he would surely die.  Despite the countless millions and billions of human deaths since that first transgression, most people still live their whole lives in denial of what God says about sin.
Eve fudged on the solemn warning from God when she misquoted it to the serpent.  "God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die" (Genesis 3:4b).  "Lest ye die" sounds more like a forecast calling for chance of showers.  This kind of substitution no doubt takes place in the minds of many who read God's absolute statement, "thou shalt surely die".King Ahaziah, the son of Jezebel, is another example of someone God sent these words to.  Ahaziah had just sent out messengers to enquire of a Philistine god whether he could expect to live after injuring himself in a bad fall.  God sent him Elijah the prophet with a message instead.  "And he said unto him, Thus saith the LORD, Forasmuch as thou hast sent messengers to enquire of Baalzebub the god of Ekron, is it not because there is no God in Israel to enquire of his word? therefore thou shalt not come down off that bed on which thou art gone up, but shalt surely die" (II Kings 1:16).

God was pointing out that by his own choice Ahaziah was denying the God of Israel.  Since he had refused the one God of salvation, there was no hope.  He would surely die.

While this may seem like a gloomy topic, it is God's desire that people know where they stand with Him as a result of their sin.  The warning gives an opportunity to turn to God and receive eternal life through the sacrifice provided by Jesus Christ.  The spiritual leader that fails to give clear warning has blood on his hands.  "When I say unto the wicked, Thou shalt surely die; and thou givest him not warning, nor speakest to warn the wicked from his wicked way, to save his life; the same wicked man shall die in his iniquity; but his blood will I require at thine hand" (Ezekiel 3:18).

"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" (Hebrews 11:7a).
The Bible puts a great deal of emphasis on the historical reality of the Great Flood, referring to both the flood and to Noah multiple times.
The record in Genesis tells us that the world became so wicked God's wrath was poured out in the waters of the flood upon everyone, but eight persons.  "And GOD saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually" (Genesis 6:5).  The reality of the Flood is confirmed in planet-wide geological and fossil evidence.  So God passed judgment on sinners on a scale that staggers the comprehension, and then left marks of the event all over the earth, along with a written record in the Bible.
In the New Testament this is cited to remind people of God's fearful wrath against sinners.  "And spared not the old world, but saved Noah the eighth person, a preacher of righteousness, bringing in the flood upon the world of the ungodly" (II Peter 2:5).  The subject of God's wrath today is avoided, evaded, mocked, argued with, and denied.  Nevertheless, God will not be shouted down, and according to Romans, "the wrath of God is revealed from heaven..." (Romans 1:18).  For God to have shown so clearly His wrath against sin leaves us all guilty and without excuse.
The Bible also tells us that our present time will lapse into a worldwide practice of sin on a scale comparable to the conditions preceding the Great Flood.  "But as the days of Noe were, so shall also the coming of the Son of man be" (Matthew 24:37).  God's solution to deteriorating conditions in our time will be the Second Coming of His Son to destroy His enemies as described in Revelation.
Before that time, we are commended to the example of Noah and his preparation for the never-seen-before calamity.  He escaped God's wrath by taking the warning seriously and trusting himself to the provision for safety prescribed by God.  Our provision today is not a large boat, but a great Saviour, Jesus Christ who came the first time to die and rise again that He might be the saviour from sin for all that receive Him by faith.