6 Significance of number 40 in the Bible

1. Moses, Elijah and Jesus fasted in the desert for 40 days each
It’s no surprise that three of the Bible’s most important figures each endured 40 days without food or water. As the ultimate test of faith, these Biblical greats used their fasts to achieve specific goals. Moses proved his loyalty to God and received the Ten Commandments. Elijah gained instruction on how to lead the people of Israel. And Jesus thwarted Satan’s temptations. In each case, they passed their tests and gained new insights into God’s ultimate plans.

2. The Israelites wandered in the desert for 40 years
After being freed from Egypt, Moses and the Israelites weren’t sure what to do next. God wanted them to find the Promised Land, but only after the generation of men who’d doubted His plan had passed. So God made the Hebrews roam the wilderness, subsisting on manna, for 40 years. Only when the last of the preceding generation was gone did God allow His people to proceed further, showing that sometimes patience is necessary to fully reveal God’s divine will.

3. Ezekiel laid on his right side for 40 days to “bear the iniquity” of Judea’s sins
The prophet Ezekiel was instructed by God to lay on his left side for 390 days and his right side for 40 days to “bear the iniquities” of Israel and Judea (respectively). The days corresponded to the number of years each kingdom insulted the name of God through wickedness and rebellion. Ezekiel suffered greatly for the sake of his forbearers, but his insights helped prepare the Israelites for the coming of Jesus.

4. Three kings reigned for 40 years each: Saul, David and Solomon
The three great Hebrew kings—Saul, David and Solomon—were each said to have ruled for 40 years. That’s no coincidence. Forty years is considered a generation in the Bible (i.e. a new group of Israelites that rises up, sustains itself, then dies off). For the three kings of antiquity, this measurement of time also contains a warning—20 years of their rule was marked by prosperity and 20 years by ruin. It characterizes the Prophet Samuel’s trepidations over instituting kings in the first place: eventually, they’ll take from the people more than they give.

5. Goliath taunted Israel for 40 days before David defeated him
Before David and Goliath became the stuff of legends, Goliath was just a massive Philistine soldier who took pleasure in humiliating the Israelites. The Philistine and Israelite armies stood on opposite sides for 40 days. Every day, a new Hebrew champion would come out to meet Goliath face-to-face, only to be destroyed. After 40 days, David, a young shepherd from Bethlehem, was sent by God to defeat the Philistines, opening a new chapter for the Israelites­—namely, the solidification of the kingdom of Israel.

6. God destroyed every living thing on Earth by flooding it for 40 days
Seeing that the sins of man had become too great, God called on Noah, a pious believer. He told him to build an ark that could hold two of every living creature on earth, as well as Noah’s family. Then God flooded His land for 40 days and nights. Once Noah and his family found the shore again, God made a covenant that He would never flood the Earth so completely again, thus re-establishing a level of trust between Him and His people that had been lost since Adam and Eve.