Re: ...Spend Out Of What We Have provided...
From my understanding of the ayah:
Ayah 2:3 "Who believe in the unseen, establish prayer, **and spend out of what We have provided for them***.*"
Who believes in the unseen … This is about having Emaan on what one have not seen.
Life in this world is test and in test we are expected to use our intelligence (what Allah has given us to differentiate, analyse and learn) to develop Emaan on things we cannot physically or materially verify (Allah who is one, Angels, life after death, judgement day, jannah, jahannum, etc). To aid and reminds us human to develop their Emaan, Allah sent prophets and books. Prophet (SAW) was last prophet and Quran was last book for humans, to aid and remind us of our test.
Establish prayer: That is obvious … that one should pray to Allah, and that one should do with belief (belief on unseen).
And spend out of what We have provided for them." … here also, it is same as establishing prayer … that is one should believe and then with that believe one should spend what Allah has given.
Actually, here in ayah, important thing that Allah wants us to remember is that, whatever we have is not ours but is given by Allah (provided to us by Allah). We are caretaker of whatever we have (so we should never think that what we have is ours). Being caretaker, we should also realise that whatever we have is test from Allah, and that test is about how we spend what we have (what is provided by Allah).
So, one should not be miser (as people who are miser thinks what they have are theirs), rather spend wherever we see what we have is needed … keeping in mind obligations Allah has put on us. We also should not become careless in our spending and throw what we have, as what we have is not ours, but we are just caretaker and we would be giving account of whatever we have to one who gave us (Allah) on judgment day.
As to how, where, and in what proportion one should spend: First obligation is to fulfil all needs of those who are our responsibility, that is spending on parents, wives, children, siblings, and then close relatives. Once their requirement is adequately fulfilled (not excessively, but adequately), and still one is left with what is provided to us by Allah, then one should spend on neighbours … and then further afar … fulfilling needs of needy adequately.
Anyhow, the word ‘adequate’ is quite vague, and here personal discretion comes into play … and that is part of this worldly test. For one person adequate could be having dinner twice a week in nice restaurant (considering eating out daily as excessive), while other might consider even eating out once a week as waste.
Best answer in determining ‘adequate’ is: One should put oneself in the shoe of people who Allah has not provided (as their existence is test for those who are provided). Then think that if they were needy, what they would have considered adequate for people who are provided.
Anyhow, Allah has created us and Allah knows our strengths and weaknesses, so, even though it is very difficult to get provided and still deprive oneself (and close ones), one should do their best keeping in mind that whatever they have is not theirs, they have responsibility towards those who are not provided, and that Allah would take account of everything what one have (what Allah provided us with).