Sayyidah Asma bint Abi Bakr (may Allah be pleased with her) said: O Messenger of Allah! I have no wealth except what al-Zubayr brings into the house. May I give a little of it in charity? He (peace and blessings be upon him) said: "Keep giving a little as much as you are able, and do not tie up the mouth of your purse, otherwise Allah will tie up (His provision) against you."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20624