“…Go to My brothers and say to them, I ascend to My Father and your Father, and My God and your God.” ~John 20:17b

In John 15:15 the Lord refers to His disciples as His friends but in John 20:17 He refers to them as His brothers. This is because when the Lord died and resurrected all the believers were regenerated with His life making them His brothers (1 Pet 1:3). This is also seen in the one grain falling into the ground and dying to produce much fruit (John 12:24).