Many of our sayings are biblical in origin. Has their recent meaning stayed true to their original intent? Most have, but not all.
Salt of the earth: The best people, especially those most dependable. It had a slightly different mean in Matthew 5:13. Jesus describes his apostles as being “the salt of the earth.” In Jesus’ time, salt was used to preserve and purify. Therefore, disciples were to help mortal souls become purified and preserve their religious beliefs.
Seventh heaven: State of blissful happiness. Jews recognize seven heavens; the highest was the seventh and was the home of God. Muslims also believe in seven heavens. Seven is the place of divine light and pure happiness.
Spirit is willing but the flesh is weak: Even though we may want to say no to something tempting, our bodies cannot resist it. Jesus says to the apostles before he goes to the Garden of Gethsemane, “Watch and pray you do not enter into temptation: the spirit is willing but the flesh is weak.” Matthew 26:41.
Drop in the bucket: A very small portion of the whole. "Behold, the nations are as a drop of a bucket, and are counted as the small dust of the balance: behold, he takes up the isles as a very little thing." Isaiah 40:15
Do not cast pearls before swine: Do not offer something of value to those who cannot appreciate it. “Neither cast you your pearls before swine.” Matthew 7:6. The biblical text is generally interpreted to be a warning by Jesus to his followers that they should not offer doctrine to those who were unable to value and appreciate it.
There is nothing new under the sun: Everything that has been done will be done again; everything that has happened will happen again. "What has been is what will be, and what has been done is what will be done. There is nothing new under the sun." Ecclesiastes 1:9
The handwriting is on the wall: Disaster or danger is imminent (without handwriting in modern times.) “In the same hour came forth fingers of a man's hand, and wrote over against the candlestick upon the plaster of the wall of the king's palace: and the king saw the part of the hand that wrote. Then the king's countenance was changed, and his thoughts troubled him, so that the joints of his loins were loosed, and his knees smote one against another.” Daniel 5:5-6
Bats in the belfry: Crazy, mentally ill. The upper part of church, the belfry, is often known as the brain of the church. Bats clutter or fly around it when distracted by the bell like confused thoughts in a disorder mind.
Land of Nod: Sleep. People sometimes nod their heads if they drop off to sleep while sitting up. Nod is mythical place but has its origin in Genesis in a much angrier context when God is chastising Cain after Cain kills his brother. “And the Lord said unto him, 'Therefore whosoever slayeth Cain, vengeance shall be taken on him sevenfold.' And the Lord set a mark upon Cain, lest any finding him should kill him. And Cain went out from the presence of the Lord, and dwelt in the land of Nod, on the east of Eden.” Genesis 4:16
In the blink of an eye: When something happens very quickly. In the New Testament, Paul talks about what will happen when Jesus Christ returns to earth, saying, “We shall all be changed in a moment, in the twinkling of an eye, at the last trumpet. The trumpet will sound and the dead rise and we will all be changed.” 1 Corinthians 15:52
Kiss of death: Something that is ultimately ruinous, destructive, or fatal. This is an allusion to the scene where Judas approaches Jesus and tries to give Jesus a kiss to identify him to the Temple guards coming to arrest him. Jesus sees Judas and stops him by asking: "Judas, are you betraying the son of man with a kiss?" Luke 22:47-48
A multitude of sins: A number of undesirable actions. “Above all hold unfailing your love fore one another, since love covers a multitude of sins.” Peter 4:8
Chapter and verse: Detailed information. This refers to the bible as the ultimate authority.
The ends of the earth: A long way away; the farthest one can go. “And I will cut off the chariot from Ephraim, and the war horse from Jerusalem, and the battle bow shall be cut off: and he shall speak peace unto the nations: and his dominion shall be from sea to sea, and from the river even to the ends of the earth.” Zechariah 9:10