12Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all people, because all sinned—
From my understanding thats why God sent Jesus. So that we didnt have to suffer eternally for the sins of Adam, or for our own sin, although we definately do deserve it, because we all sin.
Why would God allow temptation in the first place?
I dont think anyone really knows the answer to that question. We do know God loves us. We do know we only see a small part of the picture while God see's it all. We dont know the answer, however we put our trust and faith in God, that his plan, and understanding is greater then ours, and that it does come from love.
19For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous.
20The law was brought in so that the trespass might increase. But where sin increased, grace increased all the more,
21so that, just as sin reigned in death, so also grace might reign through righteousness to bring eternal life through Jesus Christ our Lord.
it is written: "What no eye has seen, what no ear has heard, and what no human mind has conceived" -- the things God has prepared for those who love him--
11As Scripture says, “Anyone who believes in him will never be put to shame.”
e 12For there is no difference between Jew and Gentile—the same Lord is Lord of all and richly blesses all who call on him,
13for, “Everyone who calls on the name of the Lord will be saved.”