Nahum 1:7 The Lord is good, a stronghold in the day of trouble; and He knows those who trust in Him.
The people from Nineveh heard what Jonah said and they repented of their evil ways; but a few generations down the line and it was all bad again.
Unless we continue to pass on the Gospel to the next generation, they have no hope in finding Christ as their friend.
It is easier to show people the truth than to try and teach them after the fact because it is easier to rest in God than to wrestle with Him!
Show people how much God means to you now.