A witness provided a testimony. A witness for God would provide the testimony of truth in the name of Christ, who is truth. (John 14:6) Thus, one is a witness for both God and Christ, since Jesus was the Word, the Logos, (John 1:1,7) and gave testimony, a witness, to the word of God, and God Himself. And God gave testimony to the Son. (Isa 55:1-5; John 1:7; 1 John 1:5)
“Even if we accept human testimony, the testimony of God is greater. For this is the testimony that God has given about His Son. 10Whoever believes in the Son of God has this testimony within him; whoever does not believe God has made Him out to be a liar, because he has not believed in the testimony that God has given about His Son.” 1 John 5:9-10
“You are my witnesses”—
this is the Lord’s declaration—
“and my servant whom I have CHOSEN,
so that you may know and believe me
and understand that I am he.
No god was formed before me,
and there will be none after me.” Isa
43:10
"The people I formed for myself (for God) will declare my PRAISE. Isa 43:21
“But you are a CHOSEN race,* a royal priesthood, a holy nation, a people for his possession, so that you may proclaim the PRAISES of the one who called you out of darkness into his marvelous light. Once you were not a people, but now you are God's people; you had not received mercy, but now you have received mercy.” 1 Pet 2:9,10
“As you come to him, a living stone—rejected by people but CHOSEN and honored by God— 5 you yourselves, as living stones, a spiritual house, are being built to be a holy priesthood to offer spiritual sacrifices acceptable to God through Jesus Christ. 1 Pet 2:4-5
The chosen priesthood belongs to God. But Jesus said, “All that belongs to the Father is mine.” (John 16:15) And, “You did not choose me, but I chose you and appointed you so that you might go and bear fruit—fruit that will last—and so that whatever you ask in my name the Father will give you.” (John 15:16)
Bearing witness “in the name of Jesus”, is the same as bearing witness in the name of the Father. Jesus carried the name of the Father while on earth, in his name.
“Remember your leaders who have spoken God’s word to you. As you carefully observe the outcome of their lives, imitate their faith. Therefore, through him (through Jesus Christ) let us continually offer up to God a sacrifice of PRAISE, that is, the fruit of lips that confess his name. 16 Don’t neglect to do what is good and to share, for God is pleased with such sacrifices.” Hebrews 13:7,15
Mal 2:7 - For the lips of a priest should guard knowledge, and people should desire instruction from his mouth, because he is the messenger of the Lord of Armies.”
God’s anointed priests are to give witness to the word of God, to truth in Jesus Christ. Matt 28:19-20
The apostle Paul: “Nevertheless, I have written to remind you more boldly on some points because of the grace given me by God 16 to be a minister of Christ Jesus to the Gentiles, SERVING AS A PRIEST of the gospel of God. God’s purpose is that the Gentiles may be an acceptable offering, sanctified by the Holy Spirit. 17 Therefore I have reason to boast in Christ Jesus regarding what pertains to God. Romans 15:15-17
The duties of an anointed priest today is to continues in the way of the early apostles.
1 Cor 4:1 - A person should think of us in this way: as servants of Christ and managers of the mysteries of God.
Except in the Wt., where they are told to be silent and “preach” only what a wicked slave tells them to, which is their own blasphemous doctrine - giving “witness” to lies and their idol/organization. (Rev 18:4-8)