The Buddha has states why he teaches rebirth post mortem
MN 68"So, Anuruddha, it is not for the purpose of scheming to deceive people or for the purpose of flattering people or for the purpose of gain, honour, and renown, or with the thought " let people know me to be thus", that when a disciple has died, the Tathagata declares his reappearance thus "so-and-so has reappeared in such-and-such a place" Rather, it is because there are faithful clansmen inspired and gladdened by what is lofty, who when they hear that, direct their minds to such a state, and that leads to their welfare and happiness for a long time"
1. of majestic or imposing height
2. morally admirable: lofty ideals
3. unpleasantly superior: a lofty contempt
What do you all think? Rebirth is just a morally admirable or lofty idea?