Mankind is alienated from God. That's why those who are disciples of Christ have been to the top of the mountain must come back down with a purpose. If we have been reconciled with God, made right in our relationship with Him, it makes sense that God would use us to help others be reconciled with Him. He will also help us find reconciliation in our own relationships and use us to help others find reconciliation in theirs. The seventh beatitude speaks to the mission of those who are part of God's solution.