Ephesians 6:5-7

‘Bondservants be obedient to those who according to the flesh are your masters, with fear and trembling (with greatest care), in singleness of your heart, as to Christ. Not in the way of eyeservice as men-pleasers, but as bondservants of Christ, doing the will of God from the heart, doing service with good will as to the Lord and not to men.'

This applies to all types of service, including that of employees and the self-employed. All service is to be performed with the sole purpose of pleasing Christ, who sees exactly what effort is put in and what care is taken. (He also sees what is invoiced). They must act as though they were bondservants of Christ. For dedicated and careful work is pleasing to God. And all such work should be done cheerfully and gladly as being done for the Lord. Genuine work is as much a spiritual service as worship.