John the Baptist answered his questioners with a sentence that I have heard called the “hope and the despair” of all mankind. John told them that “a man can receive nothing, unless it has been given to him from heaven.”
John was speaking of spiritual truth that comes only by God’s Holy Spirit, and can be received only by spiritual revelation. In Acts 7 we see a spiritual revelation given to Stephen from heaven at the time of his martyrdom.
The Bible speaks again and again of the failure of human reason to discover or comprehend divine truth. In that failure we see human despair.
John the Baptist said, “…unless it has been given to him from heaven”! This means that there are gifts that come from heaven. And Jesus promised His disciples that the Holy Spirit of truth would come and teach them all things (see John 16:13-14).