The influence of Tawhid i.e., worshipping Allah Alone in this life, has been manifested in the Ayahs (Qur'anic verses) in which Allah (Exalted be He) says:
Allâh has promised those among you who believe and do righteous good deeds, that He will certainly grant them succession to (the present rulers) in the land, as He granted it to those before them, and that He will grant them the authority to practise their religion which He has chosen for them (i.e. Islâm). And He will surely give them in exchange a safe security after their fear (provided) they (believers) worship Me and do not associate anything (in worship) with Me.
(Part No. 2; Page No. 433) And:
It is those who believe (in the Oneness of Allâh and worship none but Him Alone) and confuse not their belief with Zulm (wrong i.e. by worshipping others besides Allâh)
Zhulm here means Shirk (associating others with Allah in His Divinity or worship),
...for them (only) there is security and they are the guided.
In these two Ayahs, Allah has manifested
the effects of Tawhid on people in this World and in the Hereafter by the prevalence of security, exchange of misguidance for true guidance, succession on earth and deepening religion in hearts and deeds.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.