Sebastian, it seems to me testimony is a good word! 1 John 1 starts out - (hopefully memory serves, but please check up on me...) "Something which has existed since the beginning, which we have heard, which we have seen with our own eyes, which we have watched and touched with our own hands, the word of life, this is our theme. That life was made visible, we saw it and are giving our testimony, declaring to you all that we have seen and heard so that you too might share our life."
I would highly recommend starting in the Gospel of John. The books that quote Jesus and are about just his life and ministry are called the Gospels, literally the "good news". Blessings on your reading!!!! I am super blessed by this question!