Then Allah says to His Messenger that He has revealed the Book to him to explain the truth to mankind in matters which they dispute over. So the Qur'an is a decisive arbitrator for every issue that they argue about.

﴿وَهَدَى﴾

(and (as) a guidance) meaning, for their hearts.

﴿وَرَحْمَةً﴾

(and a mercy) meaning, for the one who adheres to it.

﴿لِّقَوْمٍ يُؤْمِنُونَ﴾

(for a people who believe.) Just as Allah causes the Qur'an to bring life to hearts that were dead from disbelief, so He brings the earth to life after it has died, by sending down water from the sky.

﴿إِنَّ فِى ذلِكَ لآيَةً لِقَوْمٍ يَسْمَعُونَ﴾

(Surely that is a sign for people who listen.) meaning those who understand the words and their meanings.

﴿وَإِنَّ لَكُمْ فِى الاٌّنْعَـمِ لَعِبْرَةً نُّسْقِيكُمْ مِّمَّا فِى بُطُونِهِ مِن بَيْنِ فَرْثٍ وَدَمٍ لَّبَنًا خَالِصًا سَآئِغًا لِلشَّارِبِينَ - وَمِن ثَمَرَتِ النَّخِيلِ وَالاٌّعْنَـبِ تَتَّخِذُونَ مِنْهُ سَكَرًا وَرِزْقًا حَسَنًا إِنَّ فِى ذلِكَ لآيَةً لِّقَوْمٍ يَعْقِلُونَ ﴾

(66. And there is indeed a lesson for you in the An'am (cattle). We have made a drink for you out of what is in its belly, from between excretions and blood, pure milk; palatable to the drinkers.) (67. And from the fruits of date palms and grapes, you derive strong drink and a goodly provision. There is indeed a sign in this for those of reason.)