The Stories - 28:82
"Those who envied him on the previous day said: "So Allah gives abundant provision to whomsoever of His servants He wills and withholds it from whomsoever He wills. If Allah had not favored us, He would have made us fail. So the disbelievers do not succeed"."
Why does he abundantly bestow or withhold blessings?
The Dawn/89:15
"When his Lord gives to man abundantly to test him, he says: "My Lord has been generous to me"."
The Dawn/89:16
"But when his Lord tests him by withholding his sustenance, he says, "My Lord has humiliated me."