Vowing to fast a month of every year until his death

Q: I was eighteen years old when I suffered from an incurable disease. I resorted to national and governmental hospitals as well as Arabic medicine for several years but to no avail. I made a vow to fast thirty days every year forever solely for the Sake of Allah, if I recovered from this malignant disease. I, praise be to Allah, recovered from this disease then got married. I have seven children now. I fasted five months before marriage and one month after marriage. I am a breastfeeding mother and fasting has a negative effect on the baby. It should be noted that since I got married I am either breastfeeding a baby or pregnant. Is it permissible for me to do anything other than fast? I appreciate your advice! May Allah reward you with the best!

A: You have to continue your fasting every year to fulfill your vow and make up for the missed months if you are able to. The Prophet (peace be upon him) said, Whoever vows to be obedient to Allah should remain obedient to Him; and whoever makes a vow to disobey Allah should not disobey Him. (Part No. 23; Page No. 309) Allah praised the believers who fulfill their vows in Surah Al-Insan which begins with: Has there not been over man a period of time by saying: They (are those who) fulfil (their) vows, and they fear a Day whose evil will be wide-spreading. We seek Allah's Help and we hope that He will grant all of us success to do what pleases Him.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.