A very powerful verse. But what places such force behind it is the word Allah uses when he says ‘none can overcome you’. He `azza wa jall says, فَلاَ غَالِبَ لَكُمْ ‘Fa-La ghaliba lakum’ – in Arabic grammar this is known as ‘lam al-nafiya lil-jins; meaning that the ‘la’ (none) indicates *a complete and total negation*. And the word ‘ghalib’ means *anything which overcomes a person*. So the verse comes to mean: There is nothing (that has the power to overcome a person) that will overcome that person if he were to be helped by Allah.
It’s very interesting, because Allah didn’t specify and say ‘human being’ for example, or ‘enemy’, or even ‘animal/beast’. He simply said ‘ghalib’. Because you see, our tests are all different. For some, they are overcome and challenged by trials with regards to people, others with wealth, others with health, and yet others with themselves! Your ‘ghalib’ might be different to my ‘ghalib’ and so on. A hundred and one things could overwhelm a person and Allah knows this, hence it is reflected in His Choice of Words in this particular ayah.
So for the believing Mutawakkil (who relies on Allah), everything is rendered powerless when the Help of Allah comes. So seek help in Allah.