The text of “Parshat ha-Mahn”:
hen G-d said to Mosheh, “I’ll rain down bread from heaven for you. The people are to go out each day and gather enough for that day. In this way I’ll test them and see whether they’ll follow My instructions. On the sixth day they are to prepare what they bring in, and that is to be twice as much as they gather on the other days.”
So Mosheh and Aharon said to all the B’nai Yisrael [Israelites], “In the evening you’ll know that it was G-d who brought you out of Egypt, and in the morning you’ll see the glory of G-d, because He has heard your grumbling against Him. Who are we, that you should grumble against us?” Mosheh also said, “You’ll know that it was G-d when He gives you meat to eat in the evening and all the bread you want in the morning, because He has heard your grumbling against Him. Who are we? You’re not grumbling against us, but against G-d.”
Then Mosheh told Aharon, “Say to the entire B’nai Yisrael, ‘Come before G-d, for He has heard your grumbling’.”
While Aharon was speaking to the whole B’nai Yisrael, they looked toward the desert, and there was the glory of G-d appearing in the cloud.
G-d said to Mosheh, “I’ve heard the grumbling of the B’nai Yisrael. Tell them, ‘At twilight you’ll eat meat, and in the morning you’ll be filled with bread. Then you’ll know that I’m the L-rd your G-d.’”
That evening, quail came and covered the camp, and in the morning there was a layer of dew around the camp. When the dew was gone, thin flakes like frost on the ground appeared on the desert floor. When the B’nai Yisrael saw it, they said to each other, “What is it?”, for they didn’t know what it was.
Mosheh said to them, “It’s the bread G-d has given you to eat. This is what G-d has commanded: ‘Everyone is to gather as much as they need. Take an omer for each person you have in your tent’.”
The B’nai Yisrael did as they were told; some gathered much, some little. And when they measured it by the omer, the one who gathered much didn’t have too much; the one who gathered little didn’t have too little. Everyone had gathered just as much as they needed.
Then Mosheh said to them, “No one is to keep any of it until morning.”
However, some of them paid no attention to Mosheh; they kept part of it until morning, but [then] it was full of maggots and began to smell. So Mosheh was angry with them.
Each morning, everyone gathered as much as they needed, and when the sun grew hot, it melted away. On the sixth day, they gathered twice as much — two omers for each person — and the leaders of the community came and reported this to Mosheh. He said to them, “This is what G-d commanded: ‘Tomorrow is to be a day of sabbath rest, a holy sabbath to G-d. So bake what you want to bake and boil what you want to boil. Save whatever is left and keep it until morning’.”
So they saved it until morning, as Mosheh commanded, and it didn’t stink or get maggots in it. “Eat it today,” Mosheh said, “because today is a sabbath to G-d. You won’t find any of it on the ground today. Six days you are to gather it, but on the seventh day, the Sabbath, there won’t be any.”
Nevertheless, some of the people went out on the seventh day to gather it, but they found none. Then G-d said to Mosheh, “How long will you refuse to keep my commands and my instructions? Bear in mind that the L-rd has given you the Sabbath; that is why on the sixth day He gives you bread for two days. Everyone is to stay where they are on the seventh day; no one is to go out.” So the people rested on the seventh day.
The people of Israel called the bread “manna.”It was white like coriander seed and tasted like wafers made with honey. Mosheh said, “This is what G-d has commanded: ‘Take an omer of manna and keep it for the generations to come, so they can see the bread I gave you to eat in the wilderness when I brought you out of Egypt’.”
So Mosheh said to Aharon, “Take a jar and put an omer of manna in it. Then place it before G-d to be kept for the generations to come.”
As G-d commanded Mosheh, Aharon put the manna with the tablets of the Torah, so that it might be preserved. The B’nai Yisrael ate manna forty years, until they came to a land that was settled; they ate manna until they reached the border of Canaan.
So, why are there traditions of reciting this on the Tuesday of the week of Parshah Beshallach, or even daily all year? 
It doesn’t seem be because the words themselves have an influence on us that other words in Torah don’t, or couldn’t, have.
Rather, it seems to be urging us to impress an idea on or over our own thinking, in order to create or enhance our sense of emunah — faith.
The essence of that idea is that G-d’s help for us is in no way limited to nature, natural circumstances or natural law. Absolutely anything is possible.
That in itself needs and deserves greater discussion.
But: How do we have faith? How do we develop it? How do we invoke it at times when it’s especially needed?
The rabbis are telling us that “faith” isn’t simply a pleasant feeling. It’s an actual change in our thinking; a change in our view of what’s happening to us. Among other ways, we bring about that change by impressing on our minds the “evidence” that tradition has given us about G-d’s interventions in the lives of others; interventions that themselves weren’t confined within “natural” limits. That “evidence” can be narratives from TaNaCh; aggadot and sippurim (stories); even straight-forward statements by writers and teachers like the Ramban, the Hovot ha-Levavot, Hasidic rebbes, and so on:
“For any person, bitachon can be a source of tranquility and happiness through the vicissitudes of life. Many read the story of the manna  every day to strengthen their bitachon. Reading and telling stories of others who lived on bitachon also helps. But nothing helps more than meditating deeply upon the deep relationship we each have with the Source of All Good, and putting that conviction to work for you whenever necessary.” 
Above, Rabbi Freeman points out that “telling” stories of other’s bitachon or emunah can be another way of raising our own. Rebbe Nachman of Breslav teaches this, too, writing of it as “direct Light” and “reflected Light”: When we tell a story of faith to inspire a friend, we produce “direct Light.” At the same time, the same Light “reflects” off that person and inspires our faith, too.
But as Rabbi Freeman says, it’s not enough just read or tell the stories, just as it’s not enough simply to repeat an affirmation carelessly. To go further, we must:
1 — Meditate deeply on the reality of the relationship we have with G-d, Who is creating and re-creating us and everything else from moment to moment.
2 — Apply that conviction to our current circumstances.
 Sh’mot/Ex. 16:4-36
 Rabbi Tzvi Freeman