Meaning: Put aside some money for future challenges or emergencies.
Choice of Words: Save: keep money, rainy day: difficult time, for: intended purpose
Alternative Expressions
Put money away for a time of need.
Meaning: This means the same as the first sentence, to set aside some of your money for a time when you might need it.
Choice of Words:Put is a verb that means to place something somewhere. Money is the currency that we use to buy things. Away means to create distance from the current location or to move from the speaker. Time of need is a phrase that means a time when you need something. When you put them together, "Put money away for a time of need" means to set aside some of your money for a time when you might need it.
Set aside some of your money for a future emergency.
Meaning: This means the same as the first two sentences, to set aside some of your money for a time when you might need it.
Choice of Words:Set aside is a verb that means to put something away for later use or to keep something from being used. Money is the currency that we use to buy things. Future emergency is a phrase that means a time in the future when you might need extra resources. When you put them together, "Set aside some of your money for a future emergency" means to put some of your money away for a time when you might need it.