I found Piper’s explanation helpful, especially when I am trying to explain to church members what it means to study the Bible.
“The work of the Spirit [illumination] is not to tell us what the manual of operation [Bible] means. That we must determine by a disciplined study of the text. The Spirit inspired these writings and he does not short-circuit them by whispering in our ear what they mean. When we pray for his help, we do not pray that he will spare us the hard work of rigorous reading and reflection. What we pray is that he would make us humble enough to welcome the truth. The work of the Spirit in helping us grasp the meaning of Christ’s manual of operation is not to make study unnecessary but to make us radically open to receive what our study turns up, instead of twisting the text to justify our unwillingness to accept it.”