The following is the most important scripture cross NT text from the earliest period soon after the crucifixion, verifying the reliability of the most important beliefs within Peter's Jerusalem sect within the 4 gospels that were all written later. If the text was incorrect, there were large numbers of actively involved still living eyewitnesses and followers that would have corrected it.
1 Corinthians 3 (Paul writing NASB20)
3 For I handed down to you as of first importance what I also received, that Christ died for our sins according to the Scriptures, 4 and that He was buried, and that He was raised on the third day according to the Scriptures, 5 and that He appeared to Cephas, then to the twelve. 6 After that He appeared to more than five hundred brothers and sisters at one time, most of whom remain until now, but some have fallen asleep; 7 then He appeared to James, then to all the apostles; 8 and last of all, as to one untimely born, He appeared to me also.
9 For I am the least of the apostles, and not fit to be called an apostle, because I persecuted the church of God. 10 But by the grace of God I am what I am, and His grace toward me did not prove vain; but I labored even more than all of them, yet not I, but the grace of God with me. 11 Whether then it was I or they, so we preach and so you believed.
12 Now if Christ is preached, that He has been raised from the dead, how do some among you say that there is no resurrection of the dead? 13 But if there is no resurrection of the dead, then not even Christ has been raised; 14 and if Christ has not been raised, then our preaching is in vain, your faith also is in vain. 15 Moreover, we are even found to be false witnesses of God, because we testified against God that He raised Christ, whom He did not raise, if in fact the dead are not raised.
16 For if the dead are not raised, then not even Christ has been raised; 17 and if Christ has not been raised, your faith is worthless; you are still in your sins. 18 Then also those who have fallen asleep in Christ have perished. 19 If we have hoped in Christ only in this life, we are of all people most to be pitied.