In this video, Venaloid explain the history of the Gospels and how they do not provide good evidence for the life, death, or resurrection of Jesus. Sources listed below.
This video makes a relatively conservative case against the reliability of the Gospels, but it is still enough to shake the foundation.
1 - Gospels are anonymous.
2 - Gospels are anonymous.
Harris, Stephen L., Understanding the Bible. Palo Alto: Mayfield. 1985.
3 - None of the Gospels claim to be eyewitnesses.
4 - A timeline of the authorship of the Gospels.
5 - A timeline of the authorship of the Gospels.
6 - Mark-Q Theory
7 - The Mark-Q theory is the most widely accepted theory.
8 - Mark verses 9-20 were added later.
Bruce Metzger, A Textual Commentary on the Greek New Testament, 2nd edition, (Hendrickson Publishers, 2005), 123.
"Clement of Alexandria and Origen [early third century] show no knowledge of the existence of these verses; furthermore Eusebius and Jerome attest that the passage was absent from almost all Greek copies of Mark known to them."
"The last twelve verses of the commonly received text of Mark are absent from the two oldest Greek manuscripts (? and B), 20 from the Old Latin codex Bobiensis, the Sinaitic Syriac manuscript, about one hundred Armenian manuscripts, 21 and the two oldest Georgian manuscripts (written a.d. 897 and a.d. 913)."
9 - Mark verses 9-20 were added later.
Bible Gateway http://www.biblegateway.com/passage/?search=mark+16&version=NIV
10 - Mark verses 9-20 were added later.
Funk, Robert W. and the Jesus Seminar. The acts of Jesus: the search for the authentic deeds of Jesus.HarperSanFrancisco. 1998. "Empty Tomb, Appearances & Ascension" p. 449-495.
11 - Shorter AND Longer endings to Mark were additions to the original text.
12 - John is different and possibly a composite.
13 - Edits to John, "He who is without sin cast the first stone".
14 - Adulterous woman story was added later.
15 - John is a composite work not intended to be taken literally.