بسم الله الرحمن الرحيم
[Note: I haven’t forgotten to reply to all your comments. It’s on my to-do list (along with a whole bunch of other stuff…).]
So, Allah says that because He is the Ever Living One, we need to put our trust in Him.
Think about it. Anyone else that we might depend upon like a family member, a friend, etc is just a created being who is going to die one day.
And what happens if they die BEFORE us?
Are we going to rely upon someone else?
And what happens if they too die BEFORE us?
See how it goes? None of them can be relied upon completely.
Allah, on the other hand, will never die so we should feel completely relaxed and put our trust in Him.