This Bible contradiction is from the EvilBible.com.

Verses

Abraham begat a son when he was a hundred years old, by the interposition of providence

Genesis 21:2 View context

For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him.

Romans 4:19 View context

And being not weak in faith, he considered not his own body now dead, when he was about an hundred years old, neither yet the deadness of Sara's womb:

Hebrews 11:12 View context

Therefore sprang there even of one, and him as good as dead, [so many] as the stars of the sky in multitude, and as the sand which is by the sea shore innumerable.

Abraham begat six children more afterward without help

Genesis 25:1-2 View context

Then again Abraham took a wife, and her name [was] Keturah.

And she bare him Zimran, and Jokshan, and Medan, and Midian, and Ishbak, and Shuah.