(Wheresoever you may be, death will overtake you even if you are in fortresses built up strong and high!) meaning, you shall certainly die and none of you shall ever escape death. Allah said,
(Whatsooever is on it (the earth) will perish),
(Everyone shall taste death), and,
(And We granted not to any human being immortality before you). Therefore, every soul shall taste death and nothing can save any person from it, whether he performed Jihad or not. Everyone has an appointed time, and a limited term of life. In the illness that preceded his death, Khalid bin Al-Walid said, while in his bed, "I participated in so and so number of battles, and every part of my body sustained an injury due to a stab or a shot. Yet here I am, I die in my bed! Let not the eyes of the cowards ever taste sleep.'' Allah's statement,
(even if you are in fortresses built up strong and high!) means, entrenched, fortified, high and towering. No caution or fortification can ever avert death.
My neighbor passed away. This though come out from my mind : "so that's it! This is the end of the journey in the lovely world