Answered by Sayyidi al-Habib `Umar bin Hafiz (may Allah preserve him and benefit us by him).
Is there any dhikr one can do to increase aspiration in worship and serving others (khidmah)?
Any dhikr done with sincerity and presence increases a person in aspiration, nearness and light. Knowers of Allah have also said that reciting the following verse 100 times a day is one of the means of raising one’s resolve in aspiration and in worship:
هُوَ اللهُ الَّذي لا إِلهَ إِلا هو عَالِمُ الغَيْبِ والشَّهادَةِ هُوَ الرَّحْمَنُ الرَّحِيم
Huw’Allāhu’lladhī lā ilāha illā hu, ‘Ālimu’l ghaybi wash-shahadah, Hu arrahmānu’ rahīm
He is Allah, there is no deity save Him, Knower of the unseen and the seen, He is the All-Compassionate, the All-Merciful. (Al-Ḥashr, 59:22)