(The Protecting Associate)
The Protecting Friend, The Supporter, The Patron.
Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ is Al-Waliy (in Arabic: ٱلْوَلِيُّ), meaning the true protector. He is supportive and loves His servants, protecting them from evil. Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ wants victory for us and will guide mankind towards the path of righteousness.
From the root waw-lam-ya (و ل ي), which has the following classical Arabic connotations: to be near, close, nearby, to be a friend, helper, supporter, to defend, guard (lit. friendly dealing), to be in charge, to turn one toward something, to be the master, owner, lord.
Al-Waliyy refers to the attribute of Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ being a close friend or ally. He wants you to know you're protected, supported, and looked after. He provides them with peace, guidance, and success in this life and the hereafter. Now, Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ is also Al-Khaliq (The Creator), and we understand this to mean that we are His servants. But this is just one categorization of our possible relationship with Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ. There are a group of people who are His friends/allies called awliyah of Allah, friends of Allah (awliyah is the plural of wali).
Wa mai yatawallal laaha wa Rasoolahoo wallazeena aamanoo fa inna hizbal laahi humul ghaaliboon (section 8)
"And whoever is an ally of Allah and His Messenger and those who have believed – indeed, the party of Allah – they will be the predominant." — (Qur'an 5:56)
On the authority of Abu Hurayrah (may Allah be pleased with him) who said: The Messenger of Allah ﷺ said, “Verily Allah ta’ala has said: ‘Whosoever shows enmity to a wali (friend) of Mine, then I have declared war against him. And My servant does not draw near to Me with anything more loved to Me than the religious duties I have obligated upon him. And My servant continues to draw near to me with nafil (supererogatory) deeds until I Love him. When I Love him, I am his hearing with which he hears, and his sight with which he sees, and his hand with which he strikes, and his foot with which he walks. Were he to ask [something] of Me, I would surely give it to him; and were he to seek refuge with Me, I would surely grant him refuge.’” 
We can read about who the awliyah of Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ are, but we should realize it's a status that is within our grasp. We should not read these stories without feeling inspired that it's possible for us. The Qur'an states by being a believer, you are a friend of His. The question then is how can one become the foremost elect of Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ. The answer is simple, but the practice is hard. It's to be dutiful and fulfill your obligations. To do good and obey His commands. Once that's established, go the extra mile and taste the sweetness in involuntary acts which are encouraged but not mandatory. Sheikh Tosun Bayrak writes, "There is neither fear nor sadness for them (referring to the believer), for they do not know any other friend but Allah. They fear nothing except opposing Allah's pleasure."
Allaahu waliyyul lazeena aamanoo yukhrijuhum minaz zulumaati ilan noori wallazeena kafarooo awliyaaa’uhumut Taaghootu yukhrijoonahum minan noori ilaz zulumaat; ulaaa’ika Ashaabun Naari hum feehaa khaalidoon (section 34)
"Allah is the ally of those who believe. He brings them out from darknesses into the light. And those who disbelieve – their allies are Taghut. They take them out of the light into darknesses. Those are the companions of the Fire; they will abide eternally therein." — (Qur'an 2:257)
Innamaa waliyyukumul laahu wa Rasooluhoo wal lazeena aamanul lazeena yuqeemoonas Salaata wa yu’toonaz Zakaata wa hum raaki’oon
"Your ally is none but Allah and [therefore] His Messenger and those who have believed – those who establish prayer and give zakah, and they bow [in worship]." — (Qur'an 5:55)
We can see from these verses, Waliyy is mentioned as an ally, a working partner who ensures success for the believer. This encompasses one meaning of Waliyy. It can also refer to protection, as in the case of guardianship. For example, in Arabic, أولياء means parents, and someone who has "Wilayah" is said to be the authority, ruler, or legal guardian. Verses from the Qur'an that reflect this quality of Al-Wali:
Wa Huwal lazee yunazzilul ghaisa min ba’di maa qanatoo wa yanshuru rahmatah; wa Huwal Waliyyul Hameed
"And it is He who sends down the rain after they had despaired and spreads His mercy. And He is the Protector, the Praiseworthy." — (Qur'an 42:28)
Inna waliyyial laahul lazee nazzalal Kitaaba wa Huwa yatawallas saaliheen
"Indeed, my protector is Allah, who has sent down the Book; and He is an ally to the righteous." — (Qur'an 7:196)
The story of Prophet Yusuf draws many parallels to Prophet Muhammad (may peace be upon them). Both were separated from their parents early in their childhood. They faced harm from the people closest to them. Yusuf (as) brothers thought about killing him, and Abu Lahab opposed protecting his nephew and used to publicly humiliate him by casting rocks and leaving excrement at his door. Those closest to them failed to provide support. Aziz, who cared for Yusus (as), acted out in his self-interest betraying Yusuf, leading to his arrest and imprisonment. And how did they respond? They turned to Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ, the only true friend a person needs. Yusuf (as) made the du'a Anta waliyyee fid dunyaa, "You are my protector in this world and in the Hereafter." (Qur'an 12:101) They are not hurt by anyone or anything because they have no expectations of others. They believe all matters are in Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ care. If you turn to Him in pleasing ways, He will grant you care and protection. It may not be as you want it to be, but trust Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ knows best.
For a second, imagine what it would feel like to be part of an inner circle of a King or someone of immense worldly success; you would be grateful for being in such a lucky position. You wouldn't want to break the trust and confidence that person has in you. Similarily, the believer benefits in knowing that Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ is Al-Wali. He has not left any of His believers stranded. He is the best friend anyone could ask for. He's the source of true success in this life and the next. We should engage in activities beloved by Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ that would raise our ranks within the inner circle of believers to try and grow nearer to Him.
Innahum lany yughnoo ‘anka minal laahi shai’aa; wa innaz zaalimeena ba’duhum awliyaaa’u ba’dinw wallaahu waliyyul muttaqeen
"Indeed, they will never avail you against Allah at all. And indeed, the wrongdoers are allies of one another; but Allah is the protector of the righteous." — (Qur'an 45:19)
 Sahih al-Bukhari 6502 & Hadith #38 an-Nawawi