In Mark’s other “afterlife” controversy (10:17-31), Jesus responds to a rich man’s question about how to “inherit” eternal life. Jesus responds by reciting from the ethical commands of the Decalogue (the Ten Commandments). The man answers “I have kept all of these since my youth.”
The concept of a heavenly afterlife for the faithful (and a hellish one for their persecutors) seems to have become appealing in Judaism during a time of great persecution: if faithfulness was not rewarded on earth, then it would be later by a just God.
Regarding a hypothetical woman who has successively outlived seven husbands, before finally dying herself, they ask: “In the resurrection, whose wife will she be? For the seven had her.”
I believe in the afterlife because I think God has “planted eternity in the human heart” (Ecclesiastes 3:11) and so it makes sense to me that there are locations to live out that eternity.