When believers of the ummah of Prophets before Muhammad (SAW), used to do good deeds their reward was less as compared to that reward given and promised to the ummah of Muhammad (SAWW). My question is why it was so? Although the salah offered at that times were 50 in a day, and Allah then reduced this number to 5 times a day for ummat-e- Muhammadya but the reward is still more than those umah. Allah reward a person for whatever good deed he does, then what could be the reason to this? Is there anything told in Quran and Sunnah to us about it?
Because as the prophet peace be upon him said in one hadith what it means that the ages (lifespan) of the people of his nation are between sixties and seventies which are very short ages compared to the ages of the previous nations. For example, Prophet Noah for example called his people for about 1000 years, his age was even longer. So as a compensation, Allah multiplied the rewards for this nation so they can do in a short lifespan as much as the previous people could do in their long lifespan.
And also because it's the last nation that comes at the end of time before the day of judgment and all fitna and trials accompanying that.
I think these are some reasons, and Allah knows best.
the only major reason, could be that all the previous prophets came with a precise specific message, for certain time and certain nation. but Quran is for whole humanity, regardless of any nation,time, or any region. Which makes the message of Quran the most special one. thats why its reward is highest. Also, Quran is the only true message till end of times as well, which makes this message very special and its ummah too