Fasting
Islam, a journey showing Allah (SWT) that you have completely submitted to Him (SWT) is manifested through fasting, one of the pillars of Islam.
Fasting is to sacrifice your desire fee-sabi-lillah (for the sake of Allah). It is a training to obtain the qualities that Allah loves, which are a sign of belonging and tasleem (submission). Submission to the will of the Almighty is always a struggle against our own carnal desires.
It requires faith, patience, and the will to behave according to what He (SWT) is pleased with at a time when Qadr (destiny) takes place or an unexpected situation is ordained for us.
This is how Allah (SWT) tests the obedience of His slaves and this is His Sunnah, or way of doing things, which will never change. We can see it in Chapter 29 Al-Ankabut as below...
Chapter 29 Al-Ankabut
In Verses 2 - 3 Allah SWT Says
Do Men Think That They Will Be Left Alone
On Saying, "We Believe",
And That They Will Not Be Tested?
We Did Test Those Before Them,
And Allah Will Certainly Know Those Who Are True
From Those Who Are False!