You are reading a tafsir for the group of verses 15:4 to 15:5
Every Township has its allotted Time
Allah is informing us that He never destroys a township until He has established evidences for it and its allotted time has ended. When the time for a nation's destruction has come, He never delays it, and He never moves its appointed time forward. This was a message and a warning to the people of Makkah, telling them to give up their Shirk, their stubbornness and disbelief for which they deserved to be destroyed.