After Christ was raised from the dead He appeared to the Apostles. Since Thomas wasn’t present, he did not believe the witness of his fellow Apostles. Eight days later when Christ appeared to them again, this time with Thomas to see for himself. This time he believed. Christ gave to His Apostles everything they needed to believe in His Resurrection. He will give YOU everything you need to believe. All you need to do is be present in the Church to see and believe.