John Wesley’s common phrase “inward and outward holiness” emphasized the essential link between heart holiness and holy living. Referring to I Peter 1:15, Wesley writes, ”perfection is another name for universal holiness – inward and outward righteousness – holiness of life arising from holiness of heart.”
First Peter 1:15 instructs us, “as he who called you is holy, be holy yourselves in all your conduct.” No dimension of life, from our attitudes and sexuality to our use of money and care of the earth, falls outside the scope of holy living. We are to have the mind of Christ (Phil 2:5), walking just as Jesus walked (I John2:6).
The Wesley Study Bible, Nashville: Abingdon Press, 2009, Page 1506.