Mark 4:33-34 records these words concerning the ministry of Jesus: “With many such parables He was speaking the word to them, so far as they were able to hear it; and He did not speak to them without a parable; but He was explaining everything privately to His own disciples.” The parables of Jesus have been studied for generations and should be revisited until His return in the clouds. The crowds to whom Jesus spoke did not often understand them. Even the disciples struggled with them, though Jesus provided an explanation privately.
After Jesus ascended, the Holy Spirit was sent to similarly aid them. In John 14:26, Jesus prophesied that the Holy Spirit would teach them all things, and John 16:13 further states that He would guide them into all the truth. Jesus was correct when He said they would profit from His departure (John 16:7). At that time, they would not need Jesus to pull them aside and explain His teaching to them. Instead, the Holy Spirit would operate on them to provide divinely inspired memories and new revelations, all the truth.
Those apostles wrote down what they heard and saw, all the truth provided by the Holy Spirit. Their inspired writings have been preserved for all people in the Bible. If the apostles were in a beneficial position when the Holy Spirit came, our generation now enjoys an even greater advantage. They had to wait for the revelation from the Holy Spirit, but today, we have all the truth bound together in the pages of the Bible.
Appreciate the opportunity and the blessing God has given you in the Bible. Open all the truth and consume it while you still have time! Obey it, and God will save you by His grace through Jesus His Son.