{Because ye are Christ's} (hoti Christou este). Predicate
genitive, belong to Christ. See  Ro 8:9  1Co 1:12  2Co 10:7 .
That is the bond of universal brotherhood of the redeemed. It
breaks over the lines of nation, race, class, sex, everything. No
service is too small, even a cup of cold water, if done for
Christ's sake. See on 烘t 18:6f.| for discussion on
stumbling-blocks for these little ones that believe on Jesus ( Mr
9:42 ), a loving term of all believers, not just children.