NET
5 Slaves, obey your human masters with fear and trembling, in the sincerity of your heart, as to Christ,
Darby
5 Bondmen, obey masters according to flesh, with fear and trembling, in simplicity of your heart as to the Christ;
KJV
5 Servants, be obedient to them that are [your] masters according to the flesh, with fear and trembling, in singleness of your heart, as unto Christ;