Sayyidah Asma bint Abi Bakr (may Allah be pleased with her) said: The Prophet (peace and blessings be upon him) came to me while I was measuring and counting something, and he (peace and blessings be upon him) said: "O Asma! Do not keep count, or Allah will keep count against you and restrict you." Sayyidah Asma (may Allah be pleased with her) said: "So after that day I never counted anything that Allah had created, nor did I number it after that day of mine."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20612