6:13 yield: 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.