Source

Isaiah 43:10 "Ye are my witnesses, saith the LORD, and my servant whom I have chosen: that ye may know and believe me, and understand that i am he: before me there was no God formed, neither shall there be after me.”

Who is a Witness

According to Mariam Webster dictionary, a witness one that serves as a pattern to be imitated or not to be imitated. A Christian witness is someone that has proven his genuineness of his faith or conviction in Christ by being a living example of what he believes. A christian witness is a living testimony and Acts 1:8

Now this man obtained a piece of land with the [money paid him as a] reward for his treachery and wickedness, and falling headlong he burst open in the middle [of his body] and all his intestines poured forth.

The verse above tells us that we shall receive power when the Holy Spirit comes upon us. God promises to make us witnesses of Him all around the world. The meaning of the statement is we are automatically witnesses because of the death of Jesus Christ. To become living witness, we can do so by telling it to others.

The Bible tells us that Christ was chosen because He gave his life making Him God's witness and His name was above any other name. As Christians, we need to start living as a witness to God's love, goodness by proclaiming it to the world
Matthew 5:16 tells us ”Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven.

Isaiah 60:1 -3: ARISE [from the depression and prostration in which circumstances have kept you--rise to a new life]! Shine (be radiant with the glory of the Lord), for your light has come, and the glory of the Lord has risen upon you!
For behold, darkness shall cover the earth, and dense darkness [all] peoples, but the Lord shall arise upon you [O Jerusalem], and His glory shall be seen on you.

Isaiah 60 tells us about our light, and to the brightness of our rising and God has made us His witness to carry the Great Commission . Apostle Paul is a living witness of the Gospel and he told the newly converted in Thessalonian ”Ye are witnesses, and God also, how holily and justly and unblameably we behaved ourselves among you that believe.”