Tafsir of Al-Hadeed 57:28

{O you who have believed} It is permissible that this is an address to those who believed from the People of the Scripture and those who believed from others.

If it is an address to the believers of the People of the Scripture, the meaning is: O you who believed in Moses and Jesus, believe in Muhammad.

{He will give you} Allah will give you.

{Two portions} Meaning: two shares.

{Of His mercy} Due to your belief in Muhammad and your belief in those before him.

{And He will make for you} On the Day of Resurrection.

{A light by which you walk} And it is the light mentioned in His saying: {Their light will proceed before them} (Al-Hadid: 12).

{And He will forgive you} What you have committed of disbelief and sins.

{So that the People of the Scripture may know that they are not able to obtain anything from the bounty of Allah, and that all bounty is in the hand of Allah; He gives it to whom He wills. And Allah is the possessor of great bounty.}