Daily Devotional by Joyce Meyer (LOOKING NICE IS NOT A SIN)
Let not yours be the [merely] external adorning with [elaborate] interweaving and knotting of the hair, the wearing of jewelry, or changes of clothes; but let it be the inward adorning and beauty of the hidden person of the heart, with the incorruptible and unfading charm of a gentle and peaceful spirit, which…is very precious in the sight of God. —1 Peter 3:3-4
Many Christians misunderstand the challenge to value inner beauty over outer appearance, as stated in the above passage. They take the concept to an extreme, believing that any effort to look nice is a sin. What Peter is encouraging us to do, however, is to resist the temptation to confuse outer beauty for what is most important, which is a gentle and peaceful spirit. In other words, don't be vain or put all your confidence in how you look, because God focuses on what is inside.
But Peter doesn't say the only way to be virtuous is to wear a brown sack, stop bathing, and give away all your possessions! True, a few people have found God by renouncing all material possessions, but I think in general it is much harder to find anything if you suffer from the constant distractions of discomfort, or if you go out of your way to be as unattractive as possible and get mistreated by others because they think you are a religious fanatic. God cares most that you go forth clothed in righteousness. But righteousness plus a nice outfit never hurt anyone! If people see that you respect yourself, they'll respect you, too.
Like everything else in life, it is a question of balance. Keep the big picture in mind. Ask yourself, What is the work that God has put me on earth to do? Then decide what amount of attention you should pay to how you look and feel to get the maximum energy, health, and charisma you need to do that work as successfully as possible.
Trust in Him: Do you spend an appropriate amount of time taking care of the body and spirit God has given you? He wants you to look your best, inside and out. Do your part to be a good steward of what He gave you, and trust Him to let you know if you are out of balance.