Peter and MJ get ready and go to the wedding of Betty Brant and Ned Leeds; they are the best man and maid of honour respectively.
PETER: You know, MJ – you’d make someone a wonderful something.
MJ: If you’re not careful Mr. Parker — I might just take you up on that.
Amazing Spider-Man #156
I LOVE unintentional foreshadowing. Not just in the dialogue but also in the fact that they’re the best man and maid of honour (tradition holds the people serving those roles wind up together). Also this issue is unintentionally ironic as of course Peter and MJ wind up having a much better marriage than Ned and Betty (which turns into a complete trainwreck).