In biblical times, the concept of underwear as understood in modern terms was not prevalent. However, garments that served a similar purpose are mentioned in the Scriptures, primarily in the context of priestly attire and modesty.

Priestly Garments:

The most explicit biblical reference to a garment resembling underwear is found in the description of the priestly garments. In Exodus 28:42, God commands Moses regarding the attire of the priests: "Make linen undergarments to cover their bare flesh, extending from waist to thigh." . These linen undergarments, known as "breeches" or "linen trousers," were worn by Aaron and his sons when they entered the Tent of Meeting or approached the altar to minister in the Holy Place. The purpose of these garments was to maintain modesty and prevent exposure, which was crucial in the sacred service to God.

Modesty and Cultural Practices:

The biblical emphasis on modesty is evident throughout Scripture, though not always directly linked to specific garments like underwear. The cultural context of ancient Israel placed a high value on modesty, particularly in worship settings. The requirement for priests to wear linen undergarments underscores the importance of approaching God with reverence and respect, avoiding any form of immodesty or indecency.

In the broader cultural context, clothing in ancient Israel was generally layered, with an inner garment (often a tunic) and an outer garment (cloak or robe). The inner garment, akin to a long shirt, served as the closest layer to the skin and provided a basic level of modesty and protection. While not underwear in the modern sense, this inner garment functioned similarly by covering the body beneath the outer layers.

Symbolism and Spiritual Lessons:

The biblical instructions regarding priestly undergarments carry symbolic significance. They highlight the need for purity and holiness when serving before the Lord. Just as the priests were required to wear specific garments to cover their nakedness, believers are called to clothe themselves with righteousness and purity. The Apostle Paul, in his letters, often uses clothing metaphors to describe spiritual truths, urging Christians to "put on the new self, created to be like God in true righteousness and holiness" (Ephesians 4:24).

Conclusion:

While the Bible does not provide extensive details on underwear as a distinct category of clothing, the references to priestly garments and the broader cultural practices of modesty offer insights into the biblical perspective on clothing and decency. These principles continue to inform Christian views on modesty and the importance of presenting oneself appropriately before God and others.Philippians 4:19
But my God shall supply all your need according to his riches in glory by Christ Jesus.
Topicalbible.org

Galatians 1:10
For do I now persuade men, or God? or do I seek to please men? for if I yet pleased men, I should not be the servant of Christ.
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Events During the War
... The next day these same men caught one of Mr. Douglas's boys, made him take off
his shoes, hat, and all his other clothing, except his underwear, and turned ...
/.../cole/trials and triumphs of faith/chapter iv events during the.htm

Letter iv. Personal Habits.
... soiled ribbons are to be shunned; but better untidiness and soil of the outward
apparel than of that which we know by the general name of underwear, which is ...
/.../letter iv personal habits.htm

Divine and Worldly Conformity
... particulars. Christian apparel should be modest in texture; that is, it should
not be so thin that it displays the body or the underwear. ...
/...//christianbookshelf.org/naylor/heart talks/talk nineteen divine and worldly.htm

Underclothing: Dictionary and Thesaurus | Clyx.com

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