Allah (swt) is satisfied with a servant who act with accordance to His method and only when Allah (swt) is satisfied with the servant, He grants him more, as Allah (swt) is Thankful and Knowledgeable.

(he is going to be satisfied) may refers to Allah (swt), Who is with His pious servants who do good deeds for the sake of His (swt) satisfaction. On the other hand, it may refer to the pious, who is satisfied with Allah’s (swt) reward and what he gets from Him (swt):

{ وَالسَّابِقُونَ الْأَوَّلُونَ مِنَ الْمُهَاجِرِينَ وَالْأَنصَارِ وَالَّذِينَ اتَّبَعُوهُم بِإِحْسَانٍ رَّضِيَ اللَّهُ عَنْهُمْ وَرَضُوا عَنْهُ }

(And the first forerunners [in the faith] among the Muhajireen and the Ansar and those who followed them with good conduct – Allah is pleased with them and they are pleased with Him,) (At-Tawba: 100)

Allah (swt) is satisfied with them, thus, He (swt) will reward them with the best.