The verse Psalms 110:4 from the King James Version (KJV) of the Bible states, "The Lord hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek." This verse is a part of a psalm attributed to King David and is considered to be a messianic psalm which prophesies the coming of the Messiah. It is important to note that Melchizedek is a figure mentioned in the book of Genesis and is later referenced in the New Testament in the book of Hebrews.

The verse speaks to the divine appointment of a priestly figure who is to be of the line of Melchizedek and is ordained by the Lord himself. In the context of the entire psalm, this verse further emphasizes the authority and power of the Messiah, who is not only a king but also a priest.

The theme of divine appointment and authority is central to this verse. The Lord's oath and refusal to repent signify the immutable nature of the divine will. This verse highlights the eternal and unchanging nature of the priesthood of the Messiah, who is appointed by God himself. It reflects the idea of divine sovereignty and the assurance that the Messiah's priestly role is of utmost significance and permanence.

The context of this verse within the psalm as a whole is important for understanding its significance. The entire psalm is a proclamation of the Lord's authority and the Messiah's role as a conqueror and king. The verse preceding it, in Psalms 110:3, speaks of the people offering themselves willingly in the day of battle, which sets the stage for the declaration of the Messiah's eternal priesthood.

The figure of Melchizedek is important in understanding the symbolism and significance of this verse. Melchizedek is a mysterious priest-king who appears in the book of Genesis, where he is described as the king of Salem (Jerusalem) and the priest of God Most High. He is a significant figure in the biblical narrative because he blessed Abraham and received tithes from him, signifying his authority and preeminence. In the New Testament, the book of Hebrews specifically references Melchizedek in relation to Jesus Christ, establishing him as a type of Christ and emphasizing his eternal priesthood.

The mention of Melchizedek in this psalm is a crucial element in the prophetic nature of the verse. It signifies the unique and exalted position of the Messiah as a priest-king after the order of Melchizedek, who is not bound by the limitations of the Levitical priesthood but holds an eternal and unchanging priesthood. The symbolism of Melchizedek as a priest-king foreshadows the dual role of the Messiah as both a king and a priest, embodying both temporal and spiritual authority.

In conclusion, Psalms 110:4 from the King James Version of the Bible conveys a powerful message about the divine appointment and eternal priesthood of the Messiah. It emphasizes the unchanging will of God and the exalted status of the Messiah as a priest-king after the order of Melchizedek. The verse holds significant theological and prophetic implications, pointing to the unique role and authority of the Messiah as the ultimate mediator between God and humanity.