Fasting makes it easier to perform acts of worship, this is evident from seeing fasting people compete and rush to perform good deeds. When not fasting, maybe they would have been lazy or found the worship difficult for them.
Shaykh Fawzān’s Ithāf Ahlul Ēmān bi Durūs Shahr Ramadhān Pg. 157
Umar Ibnul Khattaab [radiyallaahu-anhu] said:
The best of deeds is the fulfilment of what Allaah has made obligatory, refraining from what Allaah has forbidden out of fear of Him and having a truthful intention in [hoping] for what Allaah has with Him [of reward in the hereafter].
[Jaami-ul Uloom Wal-Hikam:page:379]
In The Name of Allaah, The Most Merciful The Bestower of Mercy
Shaikhul Islaam Ibn Taymiyyah (rahimahullaah) said:
‘’The performance of good deeds has praiseworthy outcomes internally and externally, and likewise sins have (evil outcomes internally and externally). Allaah (The Most High) created the means to this and the means to that, just as He (The Most High) made poison a means to falling ill and death. The means towards (performing) evil have their means to preventing their occurrence. Repentance and righteous actions wipes away evil deeds and calamities in the worldly life are an expiation for evil deeds.’’
Source: Tareequl Wusool Ilaa Ilmul Ma’mool Bi-Ma-rifatil Qawaa-id Wad-Dawaabit Wal-Usool; by Imaam as-Saa’di (rahimahullaah)