When Yeshua was sacrificed for us as our Passover Lamb, He told the women of Jerusalem, "Don't cry for Me, but for yourselves and your children .... If this happens to the Living Tree, what do you think will happen to the dead tree?" (Luke 23:28-31)
He seems to be referring at least partly to the disasters 40 years later when the Romans destroyed the city and the Temple. But He seems to be looking beyond it to other, and worse, troubles still future.
This "not a but b" grammatical structure is found often in Scripture. It often does not absolutely deny the "a", but de-emphasizes it in favor of the "b". A couple of good, clear examples are in Amos 5:25-26 (where He tells Israel, in effect, "I didn't tell you to offer sacrifices, but to follow Me.") and Romans 2:28-29. ("Jewishness is not a matter of physical birth, but of the heart.") In Luke 23, He seems to be saying that it is less important to grieve over His suffering for us than to grieve over the sorrows and sufferings of His People Israel. Perhaps He forsaw the many Easter pageants in traditionally Catholic countries over the years, where so many people grieve so enthusiastically over Yeshua's sufferings and death. But the grief didn't lead many to repent of their sins and receive God's gift of His holiness which that suffering purchased for them. Instead it sometimes motivated them to persecute Jews more. The biblical emphasis is to thank Him for His sufferings and to grieve over the sufferings His People must undergo.
Why the difference? He answers with a proverb. If you cut down a living tree, it will grow again. He will rise and enjoy a good future. So will all who follow Him. But a dead tree that is cut down is gone. That is plenty of reason to mourn.