Did the prophet have his own teachings besides the Quran?

O People of the Book, Our messenger has come to you, to 'yubayyin' (clarify) to you, after a period
of time without messengers, lest you say, "We did not receive any bearer of news nor a warner".
Indeed, a bearer of news and warner has come to you, and God is Capable of all things.

As is the case with a number of other Quranic verses presented in this section, the words in 5:19 have also been employed to justify the upholding of hadith as a second source of religious law besides the Quran. The claim is that the word "yubbayyin" in 5:19 lays a duty on the messenger to explain the Quran that was revealed to him. They add that the hadith of prophet Muhammad explains the Quran and is therefore a legitimate source of Islam.

If we accept the above interpretation of 5:19, we would immediately run into what seems like a Quranic contradiction. To demonstrate this, we need to read the following verses:

Sura 75
16- Do not move your tongue with it (O Muhammad) to hasten it.
17- Indeed, upon Us is its collection and its recitation.
18- Once We recite it, you shall follow such a recitation.
19- Then upon Us is its explanation.

The underlined words in verse 19 assert it is God, and not the messenger, who teaches and explains the meaning of the Quran in the hearts of the guided ones. The same truth that it is God who explains the Quran is given in the following words:

Al-Rahman taught the Quran.

Further confirmation of the above is found in the Quranic assurance that the only duty of the messenger is to deliver the message of God (Quran) to the people:

The sole duty of the messenger is the delivery, and God knows what you reveal and what you conceal.

O you messenger, convey what was brought down to you from your Lord. If you do not, then you have not delivered His message. 5:67

If God made it clear to the messenger that the explanation of the Quran lies on God (75:19), then why is God instructing the messenger to
"yubbayyin" (interpreted as: to explain) to the people?
As we know, there are no contradictions in the Holy Quran. The apparent contradiction can be eliminated when we use Quranic evidence to determine the correct meaning of the command to "yubbayyin" in 5:19.

The key verse which provides us with this clarification is the following:

God took a covenant from those who received the Scripture: "You shall 'tubayinunnahu' (make it clear) to the people, and not conceal it."

The words in 2:213 tell us that God revealed the Scripture to His prophets. Therefore, the words "those who received the Scripture" in 3:187 refer to the prophets of God, one of whom is prophet Muhammad.

The importance of 3:187 is that not only does it use the same verb
"yubbayyin", but it also provides us with the antonym of "yubbayyin". The antonym given by God in 3:187 for "yubbayyin" is "conceal".

And so to attain the correct context of "yubbayyin" as used in 5:19 and also 3:187, we need to perform a reverse process and determine the antonym of the word "conceal".
The antonym of (conceal) is: reveal, disclose or make clear.
It becomes evident that in the context of 5:19 and 3:187, God is commanding the messenger to make clear to the people what was revealed to him from God and not to conceal any of it. However, the task of explaining the Quran in the hearts of people lies on God (75:19).

Following this Quran analysis and clarification, all the verses make perfect sense and no contradiction lies within them.