We get to see Jin and Sun's wedding in a flashback. They exchange rings and say their vows. Jin mentions how they will never be apart, juxtaposing the actual events where he is in 1977 and she is in 2007. Also, Sun gives him his ring we she now has no the island and she gets her wedding ring which she lost and later found in the season 2 episode "...And Found."
It's worth noting that the actors who play Mr. and Mrs. Paik are not in the episode but I believe the man and woman sitting next to Aunt Soo in the eighth photo is supposed to be them.
Later, people are lined up to give their best wishes to Jin and Sun. Aunt Soo asks them when they are going to start a family and Sun says "Maybe on our honeymoon."
Next in line is the mysterious Jacob. Speaking fluent Korean, he says to them "I'd like to offer you my blessing. Your love is a very special thing. Never take it for granted." As he is speaking, he touches both of them on their arms. He then bows and walks away. Sun asks Jin who the man was and Jin says "I don't know, but his Korean is excellent."
Again we see Jacob making a point to touch both Jin and Sun. It's still seems to be very significant, but why has he touched all of our survivors thus far? What does it mean for their lives?