'Free' is ambiguous. It is justified, cleared, discharged. From sin, note, not sins.
Or 'he died,' aorist. It is the fact: see Note, ch. 5.6.
There is a distinction between the present tense, which has a continuous present sense, and the aorist, which gives the act in itself. 'Neither yield your members,' ver. 13 (present tense), means that it is at no time to be done. 'Yield yourselves to God' and 'yield your members,' ver. 15 (aorists), mean let it have been done, as a once accomplished act.
Lit. 'as out of dead alive.' The order of the words gives a contrasted force: not merely that they came thence. But 'out of dead alive' is hardly English.
Or 'are we to sin?' the subjunctive aorist.
The word translated 'in bondage' is an adjective, expressing the state of slavery, 'enslaved.'