We accept some secondary historical documents as there is nothing more concrete to contradict them George. When there is something far more concrete that suggests they're a load of shite, we dismiss them as unreliable. If the bible is the primary source for Jesus' life, then it's a pretty poor one. The bible, New or Old Testament, is a political and religious document, not a historical one. You'll be telling us Moses could control water with his mind next and there's historical evidence for it (despite there being no evidence of (i) Moses ever existing (ii) the Jews being put into slavery in Egypt (iii) the Jews ever being in Egypt.)