"AND SURELY WE WILL TEST YOU WITH A BIT OF FEAR AND HUNGER, AND LOSS IN WEALTH AND LIVES AND FRUITS. AND GIVE GOOD TIDINGS TO THE PATIENT (AL-SABIRIN) WHO, WHEN SUFFERING COMES TO THEM, SAY: "WE CERTAINLY BELONG TO ALLAH, AND TO HIM WE ARE BOUND TO RETURN." (SURAH AL-BAQARAH:155-156

وَلَنَبۡلُوَنَّكُم بِشَىۡءٍ۬ مِّنَ ٱلۡخَوۡفِ وَٱلۡجُوعِ وَنَقۡصٍ۬ مِّنَ ٱلۡأَمۡوَٲلِ وَٱلۡأَنفُسِ وَٱلثَّمَرَٲتِ‌ۗ وَبَشِّرِ ٱلصَّـٰبِرِينَ (١٥٥) ٱلَّذِينَ إِذَآ أَصَـٰبَتۡهُم مُّصِيبَةٌ۬ قَالُوٓاْ إِنَّا لِلَّهِ وَإِنَّآ إِلَيۡهِ رَٲجِعُونَ (١٥٦) سورة البقرة

In this verse the whole Ummah (community) has been addressed. What it implies is that this worldly life is a test i.e. everyone has to go through hardships in this life. If a person keeps that in mind and does not consider these hardships strange and remote (as in he doesn't start thinking that hardships are only for other people and not for him, or that he didn't deserve to come across a hardship) then he will not become impatient. As everyone comes across hardships and the Ummah generally displays the spirit of patience in all its deeds, the reward of Allah Ta'alah's blessing is common to everyone. But as the quality and degree of patience varies from person to person, everyone will be rewarded individually according to his quality of patience.

Part 2

In this verse where it says that when facing a hardship Sabirin (people who display patience) say that "To Allah we belong and to Him we shall return" it is actually teaching other people that that is what they should say when facing a hardship. Saying this at times of adversity brings great reward from Allah Ta'alah. And also, if a person says this while genuinely meaning it, saying this will reduce his worry and sorrow, and will bring great solace to his heart. 

Adapted from Ma'ariful Quran, Interpretation of Surah Al-Baqarah, by Mufti Muhammad Shafi RE