Hello @DOUGLASPAUL, yes, I'm convinced that we are ~all~ called to be His witnesses, even when we are still very young in the faith, and even though I don't believe that all of us have been specially gifted by the Holy Spirit to be evangelists .. e.g. Ephesians 4:11 (the work of an evangelist is generally different than that of a witness).
The following are a number of verses/passages that instruct us to do so, though there are others, of course. On the flipside, I can't think of any verses/passages that tell us not to do so (except in certain, temporary circumstances .. e.g. Matthew 7:6).
Isaiah 43
10 “You are My witnesses,” declares the LORD, “And My servant whom I have chosen,
In order that you may know and believe Me,
And understand that I am He.
Before Me there was no God formed,
And there will be none after Me.
11 I, even I, am the LORD;
And there is no Savior besides Me.”
Matthew 28
19 “Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit,
20 teaching them to observe all that I commanded you; and lo, I am with you always, even to the end of the age.”
Mark 16
15 Jesus said to them, “Go into all the world and preach the Gospel to all creation”.
Acts 1
8 “You will receive power when the Holy Spirit has come upon you; and you shall be My witnesses both in Jerusalem, and in all Judea and Samaria, and even to the remotest part of the earth.”
Romans 10
17 Faith comes from hearing, and hearing by the word of Christ.
1 Peter 3
15 Sanctify Christ as Lord in your hearts, always being ready to make a defense to everyone who asks you to give an account for the hope that is in you, yet with gentleness and reverence.
God bless you!!
~Deuteronomy (David)