The Iron - 57:24 Those who are stingy and advise people to be stingy. Whoever turns away, surely Allah is the Rich, the Praiseworthy.
The intention is that if you are stingy, Allah will replace you with a people who will not be stingy and will spend in the way of Allah:
The Cattle/6:133 Your Lord is Rich, the Owner of Mercy. If He wills, He will take you away and replace you with whom He wills after you, just as He brought you from the descendants of others.

Muhammad/47:38 You are called to spend in the Way of Allah, but some of you are stingy. Whoever is stingy is stingy towards himself. Allah is rich and you are poor. If you turn away, He will replace you with another people, but they will not be like you.

The Iron/57:24 Those who are stingy and advise people to be stingy. Whoever turns away, surely Allah is the Rich, the Praiseworthy.