1“Behold, I send my messenger, and he will prepare the way before me! The Lord, whom you seek, will suddenly come to his temple. Behold, the messenger of the covenant, whom you desire, is coming!” says Yahweh of Armies. 2“But who can endure the day of his coming? And who will stand when he appears? For he is like a refiner’s fire, and like launderers’ soap; 3and he will sit as a refiner and purifier of silver, and he will purify the sons of Levi, and refine them as gold and silver; and they shall offer to Yahweh offerings in righteousness. 4Then the offering of Judah and Jerusalem will be pleasant to Yahweh as in the days of old and as in ancient years.
5I will come near to you to judgment. I will be a swift witness against the sorcerers, against the adulterers, against the perjurers, and against those who oppress the hireling in his wages, the widow, and the fatherless, and who deprive the foreigner of justice, and don’t fear me,” says Yahweh of Armies.
6“For I, Yahweh, don’t change; therefore you, sons of Jacob, are not consumed. 7From the days of your fathers you have turned away from my ordinances and have not kept them. Return to me, and I will return to you,” says Yahweh of Armies. “But you say, ‘How shall we return?’
8Will a man rob God? Yet you rob me! But you say, ‘How have we robbed you?’ In tithes and offerings. 9You are cursed with the curse; for you rob me, even this whole nation. 10Bring the whole tithe into the storehouse, that there may be food in my house, and test me now in this,” says Yahweh of Armies, “if I will not open you the windows of heaven, and pour you out a blessing, that there will not be enough room for. 11I will rebuke the devourer for your sakes, and he shall not destroy the fruits of your ground; neither shall your vine cast its fruit before its time in the field,” says Yahweh of Armies. 12“All nations shall call you blessed, for you will be a delightful land,” says Yahweh of Armies.
13“Your words have been harsh against me,” says Yahweh. “Yet you say, ‘What have we spoken against you?’ 14You have said, ‘It is vain to serve God,’ and ‘What profit is it that we have followed his instructions and that we have walked mournfully before Yahweh of Armies? 15Now we call the proud happy; yes, those who work wickedness are built up; yes, they tempt God, and escape.’
16Then those who feared Yahweh spoke one with another; and Yahweh listened and heard, and a book of memory was written before him for those who feared Yahweh and who honored his name. 17They shall be mine,” says Yahweh of Armies, “my own possession in the day that I make. I will spare them, as a man spares his own son who serves him. 18Then you shall return and discern between the righteous and the wicked, between him who serves God and him who doesn’t serve him.
Jesus' statement in Mark 9:50, "'Salt is good'" is similar to how it is seen elsewhere in Scripture. "Salt" may be associated with any one of several biblical connections. In Matthew 5:13, "'You are the salt of the earth'" speaks of the preservative effect that believers have in the world. In 2 Kings 2:19-23, salt is used for purification. Its mixture with incense is called "pure and holy" in Exodus 30:35. In Colossians 4:6, the seasoning effect of salt is used to describe gracious speech. Salt also represents wisdom, in rabbinic tradition. Without necessarily having just one of these connections in mind, Jesus may have been using salt to represent whatever quality is needed to keep on being "'at peace with one another'" (v. 50).
If the call to be at peace with one another, at the end of verse 50, reaches all the way back to the disciples' discussion of who was the greatest among them (vv. 33-34), then Jesus' reference to salt, in verse 50, may be related to His statement in verse 49, "'For everyone will be salted with fire.'" Fire is a symbol of purifying judgment for believers (Matt 3:11; Luke 3:16; Mal 3:2-3), as well as of eternal torment in Gehenna (hell) for unbelievers (vv. 47-48). To be salted with fire in the sense that Jesus meant in verse 49, is to be continually purged of impurities in such a way that one's spiritual well-being is preserved. To "have salt in yourselves" (v. 50), then, means to maintain a servant's heart so as to realize freedom from the self-absorption and competitiveness that undermines peace among fellow believers.