3:9 Lie not one to another, {7} seeing that ye have put off the old man with his deeds;
(7) A definition of our new birth taken from the parts of it, which are the putting off of the old man, that is to say, of the wickedness which is in us by nature, and the restoring and repairing of the new man, that is to say, of the pureness which is given us by grace. However, both the putting off and the putting on are only begun in us in this present life, and by certain degrees finished, the one dying in us by little and little, and the other coming to the perfection of another life, by little and little.
3:9 Lie not to one another. Christ is truth, and they who are of Christ will be truth in word and deed.
Seeing that ye have put off the old man with his deeds. Lying would be a proof that the old man, the old fleshly nature, with his deeds had not been put off (Eph 4:22 Ro 6:6).
3:5-11 It is our duty to mortify our members which incline to the things of the world. Mortify them, kill them, suppress them, as weeds or vermin which spread and destroy all about them. Continual opposition must be made to all corrupt workings, and no provision made for carnal indulgences. Occasions of sin must be avoided: the lusts of the flesh, and the love of the world; and covetousness, which is idolatry; love of present good, and of outward enjoyments. It is necessary to mortify sins, because if we do not kill them, they will kill us. The gospel changes the higher as well as the lower powers of the soul, and supports the rule of right reason and conscience, over appetite and passion. There is now no difference from country, or conditions and circumstances of life. It is the duty of every one to be holy, because Christ is a Christian's All, his only Lord and Saviour, and all his hope and happiness.