John tells us what the Lord Jesus taught him, see e.g. v5.

Jesus speaks to us; can we pass it on, or are we dead? The sea of Galilee is full of life; water flows in and out, but from there it flows to the dead sea, where there is no outflow. So, when you only receive God's words, but don't pass it on, you're dead too

Some people are afraid of lightning, which is nothing in comparison to God. How much more ought we not to fear God! Think of Moses' relationship with God. He spoke to Him as a friend to a friend, but he knew the fear of God. Woe to you if you don't know the fear of the Lord. John was the beloved disciple, but when he saw Jesus in His glory in Revelations, he fell down as dead. Jesus had to lift him up and say, 'fear not'.

Corrie ten Boom and her companion went to Uganda to do missionwork. On the way they got bitter with one another and could not properly speak to each other. Those in Uganda had experienced revival in those days, and used to great one another with 1John 1:7, "Do you walk in the light as He is in the light?". Corrie and her companion did not know this, and as they met the Christians and greeted them, they greeted them back with, "Do you walk in the light as He is in the light?" Immediately they were convicted of their sin and excused themselves. They went out and asked each other forgiveness and prayed to God to forgive them. When God works in revival He leaves His mark in His work. During a revival in China, they used to greet each other with, "Are you walking in victory over sin?", and many times the other would respond that he had failed and make right his life.