All said and done, from whatever way you look at it, Tawheed in Islam is contained in 4 Phrases, namely:--
LAA ILAHA ILLALLAH
ALLAHU AKBAR and LA HAWLA WALA QUWATA ILLA BILLAH.
Taken together, these 4 phrases encompass Tawheed (worshipping Allah alone) and qadr (pre-decree).
Ibn Abi Awfaa, may Allah be pleased with him, said: a man came to the Prophet, Sallallahu alaihi Wasallam, and said:
" I cannot learn the Qur'an, so teach me something that will suffice me. He said:
[recite] Subhanallah, Walhamdulillah, Wa la ilaha illallah, Wallahu Akbar; Wa la
hawla walaa Quwata illa Billah.." [Abu Dawud 832, Nisa'ee 2/143].
Abu Hurairah, may Allah be pleased with him, reported: "Shall I inform you of a
Phrase which is under the throne and from among the treasures of Paradise?
Say, 'LA Hawla wa laa Quwata illa Billah', Allah will say, 'My Servant has
submitted himself in intention, action and worship (aslama was-taslama)'
[Hakim, Daarabi, Fathal Baari 11/501].
A servant does not control any of his affairs; he does not have the means to repel harm or the ability to attain goodness except by Allah's Will. A servant cannot change disobedience to obedience, sickness to health, weakness to strength, deficiency to perfection except by Allah's help.
What Allah wills happens and what He does not will won't happen. The affairs of creation are tied to His Decree and Pre-Destination.