Romans 7:5

For when we were in the flesh, the sinful passions which were through the law, wrought in our members to bring forth fruit unto death.

Under Romans 7:4 Paul's teaching is viewed as applicable to both Jewish and Gentile Christians, the same being essentially one "in Christ"; but this should not obscure the fact that the Jewish element in the church was primarily in the focus of Paul's words here.

In the flesh ... refers to the nature of the Mosaic covenant, primarily one of flesh. It was the connection of the chosen people with the flesh of Abraham, and the rite of circumcision, which was a mark in the flesh, that Paul had in view. It should be noted that Paul was not here contrasting two methods of salvation in Christ, as sometimes alleged, but was contrasting life under the law of Moses with the life of faith in Jesus Christ. Regarding the unbearable nature of Moses' law, Peter said,

Now therefore why make ye trial of God, that ye should put a yoke upon the necks of the disciples which neither our fathers nor we were able to bear (Acts 15:10).

The inability of the Mosaic system to give the worshiper any valid victory over sin was due: (1) to the fact that no forgiveness was possible, (2) that there was no impartation of the Holy Spirit, and (3) that there was utterly no justification in the keeping of its precepts. No wonder that Peter referred to it as a yoke of bondage.