Allah, exalted be His praise, said in praise of a people: "They fulfil their vows and fear a Day whose evil will be widespread." [Surah al-Insan: 7]
And He said in condemnation of others: "And among them are those who made a covenant with Allah: 'If He gives us of His bounty, we will surely give charity and surely be among the righteous.' But when He gave them of His bounty, they were stingy with it and turned away, and they are averse. So He put hypocrisy into their hearts as a consequence, until the Day they will meet Him, because they broke the promise they had made to Allah and because they used to lie." [Surah al-Tawbah: 75-77]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / Q20087