Destiny:

Allah says:

] مَا أَصَابَ مِن مُّصِيبَةٍ فِي الأرْضِ وَلا فِي أَنفُسِكُمْ إِلا فِي كِتَاب مِّن قَبْلِ أَن نَّبْرَأَهَا إِنَّ ذَلِكَ عَلَى اللَّهِ يَسِيرٌ[
(الحديد: 22)

This means: “No calamity befalls on the earth or in yourselves but is inscribed in the Book of Decrees (Al-Lawh Al-Mahfuz), before We bring it into existence. Verily, that is easy for Allah.” (57, Al-Hadid: 22)

Allah says:

]قُل لَّن يُصِيبَنَا إِلاَّ مَا كَتَبَ اللّهُ لَنَا هُوَ مَوْلاَنَا وَعَلَى اللّهِ فَلْيَتَوَكَّلِ الْمُؤْمِنُون[ (التوبة: 51)

This means: “Say: "Nothing shall ever happen to us except what Allah has ordained for us. He is our Mawla (Lord, Helper and Protector)." And in Allah let the believers put their trust.” (9, At-Tawbah: 51)

Allah says:

]ثُمَّ أَنزَلَ عَلَيْكُم مِّن بَعْدِ الْغَمِّ أَمَنَةً نُّعَاسًا يَغْشَى طَآئِفَةً مِّنكُمْ وَطَآئِفَةٌ قَدْ أَهَمَّتْهُمْ أَنفُسُهُمْ يَظُنُّونَ بِاللّهِ غَيْر الْحَقِّ ظَنَّ الْجَاهِلِيَّةِ يَقُولُونَ هَل لَّنَا مِنَ الأَمْرِ مِن شَيْء قُلْ إِنَّ الأَمْرَ كُلَّهُ لِلَّهِ يُخْفُونَ فِي أَنفُسِهِم مَّا لاَ يُبْدُونَ لَك يَقُولُونَ لَوْ كَانَ لَنَا مِنَ الأَمْرِ شَيْءٌ مَّا قُتِلْنَا هَاهُنَا قُل لَّوكُنتُمْ فِي بُيُوتِكُمْ لَبَرَزَ الَّذِينَ كُتِبَ عَلَيْهِمُ الْقَتْلُ إِلَى مَضَاجِعِهِمْ[
(آل عمران: 154)

This means: “Then after the distress, He sent down security for you. Slumber overtook a party of you, while another party was thinking about themselves (as how to save their ownselves, ignoring the others and the Prophet SAW) and thought wrongly of Allah - the thought of ignorance. They said, "Have we any part in the affair?" Say you (O Muhammad SAW): "Indeed the affair belongs wholly to Allah." They hide within themselves what they dare not reveal to you, saying: “If we had anything to do with the affair, none of us would have been killed here.” Say: Even if you had remained in your homes, those for whom death was decreed would certainly have gone forth to the place of their death.” (3, Al-`Imran: 154)

Advising Ibn `Abbas, when he was a child, the Prophet (peace be upon him) said:

“Remember that if all the people desire to benefit you, they will be unable to bestow anything upon you except that which Allah has preordained (for you), and if all of them agree to do you harm, they will not be able to afflict you with anything except that which Allah has predestined against you. The pens have been lifted and put aside and the ink of the book of predestination has dried up.” (Reported by At-Tirmidhi)

 

 Following mundane procedures and supplicating to Allah:

The Messenger of Allah (peace be upon him) said:

“If you get wind breaking out plague in a land do not enter it, and if it appears in land in which you happen to be, do not leave it.”
(Reported by Al-Bukhari and Muslim)

The Prophet (peace be upon him) also said:

“Caution does not prevent destiny. Yet, invocation benefits (a Muslim) concerning (the preordained things) that happened or not. So, adhere to invocation, servants of Allah.” (Reported by Ahmad)

 Believing in the unseen:

Allah says:

]الَّذِينَ يُؤْمِنُونَ بِالْغَيْبِ وَيُقِيمُونَ الصَّلاةَ وَمِمَّا رَزَقْنَاهُمْ يُنفِقُون[
(البقرة: 3)

This means: “Who believe in the Ghayb and perform As-Salah (Iqamat-as-Salah), and spend out of what We have provided for them (i.e. give Zakah, spend on themselves, their parents, their children, their wives, etc., and also give charity to the poor and also in Allah's Cause - Jihad).”
 (2, Al-Baqarah: 3)