Summary:

According to Islamic traditions, Warqa was a Christian scholar, who was the first one to give Muhammad the idea of prophethood, after Muhammad claimed an angel brought him a revelation. However, after Waraqah's death, Muhammad did not claim any further revelation for three years (link).

It seems that during those three years, Muhammad was collecting biblical stories to link his claim of revelation and prophethood with those biblical stories.

So, the question arises, what was the connection between Waraqah's death and the revelation that it had to be stopped for three years? Muslims have no answer for this. The best excuse given by Muslims for the cessation of revelation is (link):

Al-Haafiz Ibn Hajar (may Allah have mercy on him) said: The cessation of revelation refers to it being delayed for a period of time. This was so that what the Prophet felt of fear might dissipate, and so that he would long for its return. (Fath al-Bari 1/27).

This is a very strange excuse. Here again, the question arises: Why did Gabriel need to press Muhammad so hard that his condition became so severe that the revelation had to be stopped for the next three years?

Muslims never answer the WISDOM behind this.

Was the revelation stopped not for three years but only for 12 or 40 days?

Some Muslims have made the excuse that the revelation was not stopped for three years, but only for 12 or 40 days. But this excuse also fails because, according to Sahih Bukhari, Hadith 6982, during this period, Muhammad was so distressed by the cessation of revelation that he climbed the mountain several times to commit suicide. Each time, Gabriel would appear and stop him, consoling him that he was indeed Allah's true prophet.

Thus, in 12 or 40 days, a person would not be in such a desperate state that he would consider suicide even once, let alone repeatedly attempt it, and even Gabriel's repeated consolations would not suffice.

Sahih Bukhari, 6982:

6581. 'Urwa related that 'A'isha said, "The beginning [of the revelation] to the Messenger of Allah, may Allah bless him and grant him peace, took the form of the true dream in sleep. Whenever he had a dream, it was clear like the break of day. He used to go to Hira' and there he devoted himself to worship for a number of nights. He took provisions with him for that. Then he would return to Khadija and take provisions for the like of that again. This continued until the Truth came to him suddenly while he was in the Cave of Hira'. The angel came to him in it and said, 'Read!'

"The Prophet said, 'I said, "I do not read." He seized me and squeezed me until all the strength went out of me and then released me and said, "Read!" I said, "I do not read." Then he seized me and squeezed me a second time until all the strength when out of me and then released me and said, "Read!" I said, "I do not read." Then he seized me and squeezed me a third time and then released me, and then he said, "Read in the name of your Lord who created man from a blood clot. Read, and your Lord is the Most Generous. He Who taught the use of the Pen" and the ayats up to "Taught man which he knew not." (96:1-5)'

"He returned with that and his heart was quaking. He went to Khadija and said, 'Wrap me up! Wrap me up!' They wrapped him up until the state of terror had left him and then he said to Khadija, 'What is wrong with me?" He told her what had happened and said, 'I am afraid for myself.' She said, 'No, it is good news. By Allah, Allah would never bring disgrace upon you. You maintain ties of kinship, speak the truth, bear people's burdens, give hospitality to your guests and help those who have been afflicted by calamities.'

"Then Khadija then went with him to Waraqa ibn Nawfal ibn Asad ibn 'Abdu'l-'Uzza ibn Qusayy, Khadija's cousin (the son of her father's brother), who had become Christian during the Jahiliyya. He could write in Arabic and wrote as much of the Gospel in Arabic as Allah willed. He was an old man who had gone blind. Khadija said to him, 'Cousin! Listen to your nephew.' Waraqa asked him, 'Nephew, what have you seen?' The Messenger of Allah, may Allah bless him and grant him peace, told him what he had seen. Waraqa said to him, 'This is the Namus [Jibril] which Allah sent to Musa. I wish that I were still young. I wish I might still be alive when your people drive you out!' The Messenger of Allah, may Allah bless him and grant him peace, said, 'Will they drive me out?' Waraqa said, 'Yes, no man has brought anything similar to what you have brought without being treated with hostility. If I am still alive on that day, I will give you my strong support.'

"Shortly after that, Waraqa died and there was a pause in the revelation until the Prophet, may Allah bless him and grant him peace, became so sad that we heard that his sorrow several times made him want to throw himself off the tops of the mountains. Whenever he reached the peak of a mountain, Jibril would appear to him and say, 'Muhammad, you are truly the Messenger of Allah.' So his agitation was stilled by that and he would be at peace and then would return home. When the gap in the revelation was long for him, and he was moved to act as before. When he reached the peak of he mountain. Jibril would appear before him and say the like of that to him."