One Who Mourns the Churban Will See Some of the Joy of Redemption

One Who Mourns the Churban Will See Some of the Joy of Redemption:
The Kedushas Levi writes that when Chazal say (Tainis 30B) that anyone who mourns for Yerushalaim will merit (“zocheh”) seeing it with joy, the intention is that a person’s strengths stem from his thoughts. If one thinks about something a lot, he will be able to follow up on those thoughts.

If a person thinks about Yerushalaim and mourns its destruction, his thoughts will become purified. (The word “zocheh” can also mean “hizdakekus”, purification.) Once his thoughts are pure, he will immediately be able to experience a bit of the joy of Yerushalaim that will exist in the future.