Knowing Jesus is not “head” knowledge as in an academic learning process, but it is a total experience which is initiated by receiving the Holy Spirit, as it was on the day of Pentecost. Without that experience you can only know “about” Jesus and God, but they are not your friends and your relationship is not a personal one. See Acts 2:4-38 for instructions
For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people: And they shall not teach every man his neighbor, and every man his brother, saying, Know the Lord: for all shall know me, from the least to the greatest.
For I will be merciful to their unrighteousness, and their sins and their iniquities will I remember no more.