who has lost faith in God,please read the whole of Ecc chapter 3. I hope you see this cos I carried the burden from your question and asked God those questions and this morning I felt peace with that chapter. A season for everything. God's love is unconditional,your mum has lived the amount of time she should and thats it. she was not living because she wants to eat the fruit of her labour though that is what she would have wanted,she was living because God said so and now its time for her to go back to God who gave her to you in the first place. This is so painful but take heart in Ecc chapter 3. Dont try to understand everything cos you wont and the devil is waiting to take advantage of your state of mind. Love God regardless and trust him only his peace can heal you. Ehugs.
