Shaving

The main Biblical implications of shaving are as follows:

Cleansing.

Joseph, when summoned to Pharaoh’s presence, may have shaved his whole body to conform to Egyptian ideas of cleanliness (Gen 41:14). The same concept appears in the ritual that marked the leper’s recovery (Lev 14:8f.) and the Levite’s consecration to service (Num 8:7), and it is indicated in Isaiah’s figure (Isa 7:20).

Mourning.

Examples are found in Deuteronomy 21:12; Job 1:20; and Jeremiah 7:29.

Vows.

Shaving of the head followed the fulfillment of a vow (Num 6:18; Acts 18:18; 21:24); but for Samson to submit to haircutting was to renounce the divine purpose for his life (Judg 16:19).

Contempt

was expressed by Hanun’s ungracious action (2 Sam 10:4; 1 Chron 19:4).

Humiliation.

a consequence of a Corinthian woman having her hair cut off (1 Cor 11:5, 6).

International Standard Bible Encyclopedia (1915)

Shaving "with a razor that is hired" is Isaiah’s graphic figure to denote the complete devastation of Judah by the Assyrian army (Isa 7:20).