Elijah "The barrel of meal shall not waste, neither shall the cruse of oil fail" miracle or not? In 1 Kings 17:14 we have the following passage (NV):


  ‘The jar of flour will not be used up and the jug of oil will not run dry until the day the Lord sends rain on the land.’”


Now every single preacher I've heard have a literary interpretation of this passage and consider it a miracle (like the multiplying of bread and fish).

However, P.Coelho in his book "The fifth mountain" suggests that Elijah worked in that city so the jar of flour was always full as a result of his income.

The latter interpretation is also favored by the last verse:


  Now by this I know that thou art a man of God


So after the widow sees her son is alive (which was undoubtedly a miracle) is convinced about Elijah. Thus, if the flour multiplying was also a miracle, she would have probably already been convinced.

Is there anything else which might help understand whether this was indeed a miracle or not ?
It is quite explicitly mentioned as a miracle from God. How else can verse 16 be interpreted?

For the jar of flour was not used up and the jug of oil did not run dry, in keeping with the word of the Lord spoken by Elijah.

I've highlighted &quot;the jar&quot; and &quot;the jug&quot;, both singular. And it says, in keeping with the word of the Lord. So this was God's promise, not Elijah's occupation.
Furthermore, the passage implies these events happen as Elijah enters the city. Consider verses 8-16:

Then the word of the Lord came to him: ‘Go at once to Zarephath in the region of Sidon and stay there. I have instructed a widow there to supply you with food.’ So he went to Zarephath. When he came to the town gate, a widow was there gathering sticks. He called to her and asked, ‘Would you bring me a little water in a jar so I may have a drink?’ As she was going to get it, he called, ‘And bring me, please, a piece of bread.’
‘As surely as the Lord your God lives,’ she replied, ‘I don’t have any bread – only a handful of flour in a jar and a little olive oil in a jug. I am gathering a few sticks to take home and make a meal for myself and my son, that we may eat it – and die.’
Elijah said to her, ‘Don’t be afraid. Go home and do as you have said. But first make a small loaf of bread for me from what you have and bring it to me, and then make something for yourself and your son. For this is what the Lord, the God of Israel, says: “The jar of flour will not be used up and the jug of oil will not run dry until the day the Lord sends rain on the land.”’
She went away and did as Elijah had told her. So there was food every day for Elijah and for the woman and her family. For the jar of flour was not used up and the jug of oil did not run dry, in keeping with the word of the Lord spoken by Elijah.

I've highlighted some words to show the pace of the story. It all happens very fast, as soon as Elijah reaches the city gates. This implies he did not have time to find employment. Finally, he wasn't even from the area, so it is not as if he returned to a previous occupation or had business contacts there.