In with a crowd in His home, Jesus receives word that His mother and other relatives have arrived outside and are asking to see Him (Mk 3:31-35).  In response, He tells those around Him that whoever does the will of God is His mother, brother, and sister.  Jesus question (above) is one we should ask as well.  If Jesus calls those who do His will His brothers and sisters, and we know God “wills everyone to be saved and to come to knowledge of the truth” (1 Tim 2:4), then we should desire every person on earth to be our sibling in the way Jesus describes (of course, making sure we do not get lost along the way [1 Cor 9:27]).    The Lord calls us to this (cf. Mk 16:15).  God’s words to Adam and Eve to be fruitful and multiply apply here also — we are to be fruitful for the kingdom and multiply the number who come to know the Lord (or return to Him [cf. Lk 15:11-32, The Prodigal Son]).  Every time we say the Lord’s Prayer we start out with “Our Father” (Mt 6:9-13) — the one prayer Jesus explicitly taught His followers starts with a unifying and all-encompassing message.  Do we want even one person to not be in God’s good graces and thus be our sibling in His Church?