The difference between legislated and innovated acts of worship
بِسۡمِ ٱللهِ ٱلرَّحۡمَـٰنِ ٱلرَّحِيمِ
Shaikhul Islaam Ibn Taymiyyah (rahimahullaah) said: 
The (affairs of) worship through which (one) seeks to get close to Allaah (The Most High)–from them are those beloved and pleasing to Allaah and His Messenger, whether obligatory or recommended; as reported in Saheeh (Al-Bukhaari) that Prophet (sallal-laahu-alayhi-wasallaam) said that Allaah (The blessed and Exalted) said:
”And the most beloved things which My slave comes nearer to Me, is what I have enjoined upon him; and My slave keeps on coming closer to Me through performing Nawaafil (praying or doing extra deeds besides what is obligatory) till I love him, then I become his sense of hearing with which he hears, and his sense of sight with which he sees, and his hand with which he grips, and his leg with which he walks; and if he asks Me, I will give him, and if he asks My Protection (Refuge), I will protect him.” [End of quote from Shaikhul Islaam]
Concerning the meaning of the statement: ”And My slave keeps on coming closer to Me through performing Nawaafil (praying or doing extra deeds besides what is obligatory) till I love him, then I become his sense of hearing with which he hears, and his sense of sight with which he sees, and his hand with which he grips, and his leg with which he walks…”
This statement is understood to mean that when a person becomes a Wali (close friend) of Allaah [The Mighty and Majestic), then when the command of Allaah is mentioned with regards to what Allaah loves or hates, he protects his hearing from what Allaah hates and lends an ear to what Allaah loves. He also does the same with regards to what he looks at; what he grips with his hand and where he walks to. Or Allaah guides him, so that he only looks at what Allaah loves; listens to what Allaah loves and walks towards what Allaah loves.
Quote continues from Shaikhul Islaam….
And it is well known with regards to the Salah that (some) of it obligatory, such as the five daily prayers; and (some) of it is optional, such as the Qiyaamul Layl (i.e. Tahajjud prayer). Also with regards to fasting, (some) of it is obligatory and that is the fasting of the month of Ramadhaan, and (some) of it is optional, such as fasting three days every month. Also travelling to the Masjid Al-Haraam (i.e. The kabah) is obligatory; and travelling to the other two masjids–Masjid of the Prophet and Masjid Al-Aqsaa–is recommended. Also with regards to charity, (some) of it is an obligation and (some) of it is recommended, and it is what is the surplus beyond (what is) needed, as Allaah (The Most High) said: [وَيَسْأَلُونَكَ مَاذَا يُنفِقُونَ قُلِ الْعَفْوَ] ‘’And they ask you what they ought to spend. Say: “That which is beyond (what they) need.” 
And it has been reported in an authentic Hadeeth in which the Prophet (sallal-laahu-alayhi-wasallaam) said: ”O son of Adam! It is better for you if you spend (your) surplus (wealth), but if you withhold it, it is evil for you. And there is no blame (on you) if you withhold the surplus in accordance with a need, in order to spend on yourself and poor relatives. The upper hand (i.e. the one who spends) is better than the lower hand (i.e. the one who asks without a need as opposed to the self-sufficient one); and begin (charity) with your dependents.” 
To be continued..In-Shaa-Allaah
 Al-Ibaadaat Ash-Shar-iyyah Wal-Farqu Baynahaa Wa Baynal Bid’ah page: 8-9
 Bukhaari Vol 8..Hadeeth Number 6502.. Daarus Salaam]
 For further details, see Sharh Arba’een of Imaam Muhammad Bin Saaleh Al-Uthaymeen.. Pages 376-381 and Sharh Arba-een of Shaikh Saaleh Aala Shaikh pages 256-258] [Also see, Jaami-ul Uloom Wal-Hikam of Imaam Ibn Rajab pages 619-641 Daar Ibn Rajab 2002]
Soorah Al-Baqarah Ayah 219]
See Saheeh Muslim Hadeeth No 1036 as well as ‘Sharh Saheeh Muslim Vol 7-8 pages 111-113]