Predestination had already been written..
If the sustenance of a person lied within a rock
stationed in the sea, hard and smooth,
it would split open
so that it could give him what is contained therein.
Or if it lied between the teeth of a predator,
Allah would cause it to come out.
Indeed, a person either goes to the sustenance predestined for him in the Preserved Tablet;
otherwise, it would come to him.
The Prophet (may Allah’s peace and blessings be upon him) said:
“Allah has appointed an angel in charge of the womb, and the angel says: ‘O Lord, a sperm drop! O Lord, a clot! O Lord, a piece of flesh.’ Then, when Allah wills to complete its creation, the angel asks: ‘O Lord, a male or female? Wretched or blissful? How much will his sustenance be? How long will he live?’ All that is written while the fetus is still in its mother’swomb.”
[Narrated by Al-Bukhāri]
So, your sustenance is guaranteed. Pursuit of it does not make it more sure, neither does the hatred of anyone prevent it from coming.
In another Hadīth, the Prophet (may Allah’s peace and blessings be upon him) said:
“Indeed, sustenance goes after the person just as his destiny goes after him.”
[Narrated by Ibn Hibbān; Sahīh (authentic)]
The Prophet (may Allah’s peace and blessings be upon him) is also authentically reported to have said:
“No soul will die without receiving its sustenance in full.”
[Narrated by Ibn Mājah; Sahīh (authentic)]
Allah Almighty sends down the provisions in an exact measure. He is the All-Knowing of the conditions of His servants and what is best for them.
{And if Allah had extended [excessively] provision for His servants, they would have committed tyranny throughout the earth. But He sends [it] down in an amount which He wills. Indeed He is All-Aware, All-Seeing of His servants.}[Surat ash-Shūra: 27]
Ibn Kathīr (may Allah have mercy upon him) said:“He is All-Aware and All-Seeing as to who deserves opulence and who deserves poverty