Tafsir of Al-Ma'idah 5:67

"O Messenger, announce that which has been revealed to you" Convey everything that has been revealed to you. Do not fear anyone in the delivery of any part of it, nor fear that any harm might befall you.

"And if you do not, then you have not conveyed His message" If you do not convey all of it as I have commanded you, then you have not conveyed His message (some read it as risalatihi—His messages). If you fail to convey what you were tasked with, you have not performed any of it at all. This is because no part of the message is more worthy of delivery than another. If you fail to deliver some of it, it is as if you have neglected to deliver all of it—just as one who does not believe in a part of the message is like one who does not believe in any of it. Each part carries the same weight as the others, and they are, in effect, a single entity. A single entity cannot be both delivered and undelivered, or believed in and not believed in.

Ibn Abbas (may Allah be pleased with them both) said: "If you conceal one verse, you have not conveyed My messages." It is narrated from the Messenger of Allah (peace be upon him): "Allah sent me with His messages, and I felt distressed by them. Then Allah revealed to me: 'If you do not convey My messages, I will punish you,' and He guaranteed me protection, so I gained strength."

If you ask: How is the conditional statement "then you have not conveyed His message" valid as a consequence? I say: There are two interpretations:

1. If one does not comply with Allah’s command to convey the messages and conceals them, it is as if he were never sent as a messenger at all—a heinous matter whose gravity is clear. Thus, it is said: If you do not convey even the smallest part, even a single word, you are like one who has committed the heinous act of concealing the whole, just as the killing of one soul is magnified by the words: "It is as if he had slain mankind entirely" (Al-Ma'idah: 32).
2. It means: If you do not do so, you will face the punishment required for concealing the entire revelation. The cause is placed in the position of the effect. This is supported by the Prophet’s words: "Allah revealed to me: 'If you do not convey My messages, I will punish you.'"

"And Allah will protect you from the people" A promise from Allah of preservation and guardianship. The meaning is: Allah guarantees you protection from your enemies, so what is your excuse for fearing them?

If you ask: Where is this guarantee of protection, when he was wounded in the face on the day of Uhud and his incisor tooth was broken (peace and blessings of Allah be upon him)? I say: The intent is that He protects him from being killed. This has been discussed previously in Surah Al-Imran. It implies that he must endure everything short of death for the sake of Allah. How severe is the burden placed upon the Prophets (peace and blessings be upon them). It is said this was revealed after the day of Uhud and the disbelievers, as evidenced by the words: "Indeed, Allah does not guide the disbelieving people." The meaning is that He will not enable them to inflict upon you the destruction they desire.

From Anas: The Messenger of Allah (peace be upon him) used to be guarded until this was revealed. He then put his head out of a leather tent and said: "Go away, O people, for Allah has protected me from the people."