Not Spending

And those who spend their wealth to be seen by people, without believing in Allah or the Last Day

4:38And (also) those who spend their wealth in order to be seen of men, and believe not in Allah nor the Last Day. Whoso taketh Satan for a comrade, a bad comrade hath he.

Those who hoard wealth and refuse to spend in Allah’s cause should not think it is good for them. Rather, it will be a burden around their necks on the Day of Judgment.

3:180And let not those who hoard up that which Allah hath bestowed upon them of His bounty think that it is better for them. Nay, it is worse for them. That which they hoard will be their collar on the Day of Resurrection. Allah's is the heritage of the heavens and the earth, and Allah is Informed of what ye do.

Their donations are only rejected because they disbelieve in Allah and His Messenger, come to prayer lazily, and give reluctantly.

9:54And naught preventeth that their contributions should be accepted from them save that they have disbelieved in Allah and in His messenger, and they come not to worship save as idlers, and pay not (their contribution) save reluctantly.

Do not let their wealth or children impress you. Allah only intends to punish them through these in this life, and their souls will depart while they are disbelievers.

9:55So let not their riches nor their children please thee (O Muhammad). Allah thereby intendeth but to punish them in the life of the world and that their souls shall pass away while they are disbelievers.

The life of this world is but play and distraction. But if you believe and are mindful, He will give you your rewards and not ask for all your wealth.

47:36The life of the world is but a sport and a pastime. And if ye believe and ward off (evil). He will give you your wages, and will not ask of you your wordly wealth.

If He were to ask you for it and press you, you would withhold, and He would expose your greed.

47:37If He should ask it of you and importune you, ye would hoard it, and He would bring to light your (secret) hates.

Here you are, invited to spend in Allah’s cause, but some of you withhold. And whoever withholds does so only against himself. Allah is free of need, while you are the needy.

47:38Lo! ye are those who are called to spend in the way of Allah, yet among you there are some who hoard. And as for him who hoardeth, he hoardeth only from his soul. And Allah is the Rich, and ye are the poor. And if ye turn away He will exchange you for some other folk, and they will not be the likes of you.