If a man is not looking after himself and becomes ill and then says: what can I do, it is Allah's will- he is wrong. You can protect yourself. If one is taking care of the body and then becoming ill anyway, then Allah is sending the illness.
A man who leaves his cows on the mountain to be eaten by wolves can't say afterwards:--"It was Allah's will that my cows die". He must protect them and put them into pens, then if they die it is Allah's will.
You have something to do with your willpower. It is not a general will, but it is enough for you, like the headlights of a car are not lighting up every place, but light enough for driving. We have such a will to arrange for our life....You may plough and plant the seeds, but you cannot rain, you can't make the grains to sprout. Allah Subhanahu Wa Ta'ala completes that plant....In order to go on Hajj, one must get his passport so as to prepare with things connected with such travel/journey, and then put the responsibility on Allah.
We have a choice, and when we have a choice, we have responsibility. One saying that he is not responsible is out of order; he is a sinner. When completing all the things you can do, then give it over to your Lord. The authority for this is in the Hadith wherein it was reported that a man once came to the Prophet, may Allah bless and grant him peace, and when asked what he had done with his camel, he replied that he had left it to the trust of Allah. The Prophet, may Allah bless and grant him peace, told him, "Tie it, then trust in Allah, 'aqil Wa tawakkil".
This gives a perfect arrangement for our lives--if you are not trying, then it is not true to say: I am trusting in Allah. When you know what you can do, you must do that. Do not neglect your responsibility...
For further reading, see
"Mercy Oceans-Book 2"
Teachings Of Shaykh Abdullah al-Dagistani.