This is a verse that is commonly used to excuse all manner of outward appearance.
1 Sam 16:7 …for man looketh on the outward appearance, but the Lord looketh on the heart. KJV
This is one of those verses that even non-Christians seem to know and throw out along with “judge not”. However, if you will look at the full passage for the phrase you will see it means much different than it is commonly claimed to mean.
1 Sam 16:7 But the Lord said unto Samuel, Look not on his countenance, or on the height of his stature; because I have refused him: for the Lord seeth not as man seeth; for man looketh on the outward appearance, but the Lord looketh on the heart. KJV
The Lord tells Samuel to “Look not on his countenance” or “on the height of his stature.” How exactly does this have anything to do with clothing? The Lord is telling Samuel to not judge David by his “countenance” meaning whether he is handsome or plain. This is not referring to clothing at all. Look at the next criteria “on the height of his stature.” This is how tall he is, not what David is wearing. David very well could have been very short.
Later in the passage, this verse is found:
1 Sam 16:12 And he sent, and brought him in. Now he was ruddy, and withal of a beautiful countenance, and goodly to look to. KJV
What does this have to do with his clothing? Not one thing, it is describing David’s physical appearance.
The Lord will judge us on our heart but we as mere men must judge only on the appearance and the fruit, not a man’s heart. A person’s outward appearance is an indicator of the condition of the heart.
A person can look perfectly modest, pure, righteous, and God fearing on the outside and have an evil, depraved, and God-hating heart. Nevertheless, a person who is modest, pure, righteous, and God fearing in the heart cannot look immodest, evil, depraved, and God hating on the outside.
Luke 6:45 A good man out of the good treasure of his heart bringeth forth that which is good; and an evil man out of the evil treasure of his heart bringeth forth that which is evil: for of the abundance of the heart his mouth speaketh. KJV
Just as out of the heart the mouth speaks, also out of the heart the clothing choices are made. Are your clothes chosen to glorify the Lord and represent Him or are your clothes chosen to glorify yourself?