(18) And it came to pass on the seventh day, that the child died. And the servants of David feared to tell him that the child was dead: for they said, Behold, while the child was yet alive, we spake unto him, and he would not hearken unto our voice: how will he then vex himself, if we tell him that the child is dead?
(19) But when David saw that his servants whispered, David perceived that the child was dead: therefore David said unto his servants, Is the child dead? And they said, He is dead.
(20) Then David arose from the earth, and washed, and anointed himself, and changed his apparel, and came into the house of the LORD, and worshipped: then he came to his own house; and when he required, they set bread before him, and he did eat.
(21) Then said his servants unto him, What thing is this that thou hast done? thou didst fast and weep for the child, while it was alive; but when the child was dead, thou didst rise and eat bread.
(22) And he said, While the child was yet alive, I fasted and wept: for I said, Who can tell whether GOD will be gracious to me, that the child may live?
(23) But now he is dead, wherefore should I fast? can I bring him back again? I shall go to him, but he shall not return to me.
I don't have to prove God's existance. He's already proven that. I just have to prove that He lives within me.
For the GRACE of God that BRINGETH Salvation hath appeared to all men, Teaching us that, DENYING ungodliness and worldly lusts, we should LIVE soberly, righteously, and godly, IN THIS PRESENT WORLD; Titus 2:11-12