In each daily prescribed prayer, we recite: Guide us to the Straight Path, to the path of those you have blessed, not of those who incurred (Your) wrath, nor of the misguided (1:5–7). The verses mention, but do not specify, two groups of people. According to the Prophet, those who incurred God's wrath are Jews who have gone astray, and the misguided are Christians who have gone astray. 
The Jews killed many of their Prophets and caused trouble in many places. Although they had once followed Divine guidance and guided others to the Straight Path (during the times of Moses, David, and Solomon), over time many of them went astray and incurred both God's wrath and public ignominy. Those who follow this way also are included in those who incurred (Your) wrath. Such Jews are condemned harshly in the Bible as well. In fact, the Bible is much harsher toward them than the Qur'an. In many verses, the Qur'an reproaches such Jews and Christians very mildly and compassionately.
At first, the Christians obeyed Jesus and followed his way despite severe persecution. They heroically resisted all forms of hypocrisy and Roman oppression. But over time, many came under the influence of various Middle Eastern religions and philosophies as well as Roman paganism. By the time Christianity became the Roman Empire's official religion, it already was divided into many sects and had more than 300 Gospels in circulation. Although many remained devoted to the original creed of Jesus, many others contaminated these pure teachings with borrowed elements. The Qur'an therefore describes them as the misguided.
By making the above interpretation, the Prophet explained how people who had been blessed with Divine guidance could go astray and end up deserving God's wrath. Thus, he warned Muslims not to follow such Jews and Christians.
Out of many examples showing how the Sunna interprets the Qur'an, we also cite the following:
• When the verse: Those who believed and did not mix their belief with wrongdoing: for them is security and they are those who are truly guided (6:82) was revealed, the Companions, well aware what wrongdoing meant, asked the Messenger fearfully: "Is there one among us who has never done wrong?" The Messenger explained: "It's not as you think. It's as Luqman said to his son: Don't associate any partners with God; surely, associating partners with God is a grave wrongdoing (31:13). 
• 'A'isha and Ibn Mas'ud are of the opinion that the mid-time prayer in: Attend the prayers without any omission and the mid-time prayer (2:238) is the afternoon prayer. Once 'A'isha ordered her servant to write a copy of the Qur'an for her and reminded her: "When you come to the verse: Attend the prayers without any omission, and the mid-time prayer, inform me." When this verse was to be copied out, 'A'isha dictated to her servant: Attend the prayers without any omission, and the mid-time prayer, the afternoon prayer, and added: "This is what I heard from the Messenger."  Although there are some other interpretations, 'A'isha and Ibn Mas'ud were certain that it was the afternoon prayer.
In addition to interpreting the Qur'an's ambiguities, the Sunna fills in the details about those subjects that the Qur'an mentions only briefly. For example, the Qur'an orders Muslims to pray properly, but does not explain how they should pray. Although some leading interpreters deduce the prayer times from such verses such as: Perform the prayer correctly at the two ends of the day and nigh of the night; surely the good deeds remove the evil deeds (11:114), the exact prayer time was established by the Prophet as follows:
On two occasions, Archangel Gabriel led me in the five daily prayers at the Ka'ba. On the first time, he prayed the noon prayer at noon, when an item's shadow was only as long as its base. When the shadow was as long as the actual item, he prayed the afternoon prayer. He prayed the evening prayer when it was time for a person to break the fast. He prayed the late evening (or night) prayer when dusk disappeared, and the dawn (or morning) prayer when those who intend to fast can no longer eat or drink. The second time, he prayed the noon prayer when an item's shadow was as long as the actual item, and prayed the afternoon prayer when it was twice as long as the actual item. He prayed the evening prayer at the same time he had prayed it previously. He prayed the night prayer after one-third of the night had passed, and the dawn prayer when it was lighter and the sun had still not risen. Then he turned to me and said: "O Muhammad, each of the five daily prayers should be performed between these two periods of time, as the Prophets before you did it." 
The Messenger also taught his community everything related to prayer: its conditions; all obligatory, necessary, and commendable acts that validate and ennoble it; and all acts that invalidate and damage it. He passed on, both through words and actions, all that they needed to know about worship. This all-inclusive term is not limited to the actual prayers, but also includes such areas as fasting, alms-giving, pilgrimage, and many more. Just as he told his followers to "pray as you see me pray," he told them to "learn from me the rites and ceremonies of pilgrimage"  after he actually performed it with his Companions. If the Qur'an had gone into such exhaustive detail on such matters, it would have been many times its present size.
The Sunna also restricts general laws and commandments in the Qur'an. For example, it lays down general principles of inheritance. When the Prophet's daughter Fatima went to Abu Bakr, the first Caliph, and asked for her inheritance, Abu Bakr replied: "I heard the Messenger say: 'The community of the Prophets does not leave anything to be inherited. What we leave is for charity." This hadith excludes the Prophets and their children from the laws of inheritance. Likewise, the Messenger decreed that "the killer (of his testator) would be disinherited."  In other words, if someone kills his or her parents, brother (sister), or uncle (aunt), they cannot inherit from them.
The Qur'an commands: And the thief, male and female, cut off the hands of both, as a recompense for what they have earned, and a punishment exemplary from God; God is All-Mighty, All-Wise (5:38). Whether this punishment is to be applied to every thief, or only to those who steal goods of a certain value, is not clear. Also, in: O believers, when you stand up to pray wash your faces, and your hands up to elbows... (5:6), the hand extends to the elbow. But the Qur'an does not mention specifically what part of the hand should be cut, nor in what circumstances this punishment should be applied. For example, during 'Umar's caliphate there was a period of famine, and he did not apply this punishment.
The Qur'an decrees: O you who believe! Consume not your goods among yourselves in vanity [through theft, usury, bribery, hoarding, and so on], except it be trade by mutual agreement (4:29). Islam encourages trade as a livelihood, as long as it is carried out according to Islamic law. One condition, as stated in the verse, is mutual agreement. However, the Messenger decreed: "Don't sell fruits until their amount is definite in the tree [so that the amount to be given as alms can be determined]" and: "Don't go to meet peasants outside the market to buy their goods [Let them earn the market prices of their goods]."
In sum, the Qur'an contains general principles that are explained by the Messenger and then applied by him to daily life. God allowed His Messenger to issue rulings, as necessary, and ordered the believers: Whatever the Messenger brings you, adopt it; whatever he forbids you, refrain from it (59:7).
 Bukhari, "Tafsir," 31/1.  Tirmidhi, "Tafsir al-Qur'an," 3.
 Abu Dawud, "Salat," 2; Tirmidhi, "Mawaqit," 1.
 Nasa'i, "Manasik," 220; Ibn Hanbal, 3:366.
 Tirmidhi, "Fara'id," 17.