God has promised over and over in the Bible, that when we need to know what to say and how to give an answer for our faith, the Spirit of the Lord shall give us wise words to speak. We need to trust Him to fulfill this promise, and we must place our faith in the Lord in the moment when we are tested.
And when they bring you to trial and deliver you over, do not be anxious beforehand what you are to say, but say whatever is given you in that hour, for it is not you who speak, but the Holy Spirit. (Mk 13:11 ESV)
The Spirit of the Lord spoke by me, and His word was on my tongue. (2 Sam 23:2)
Therefore settle it in your hearts not to meditate beforehand on what you will answer; 15 for I will give you a mouth and wisdom which all your adversaries will not be able to contradict or resist. (Lk 21:14-15, emphasis added)
But when they deliver you up, do not worry about how or what you should speak. For it will be given to you in that hour what you should speak . . . (Mt 10:19, underlining added)
If any of you lacks wisdom, let him ask of God, who gives to all liberally and without reproach, and it will be given to him. (Jam 1:5)
When we lack wisdom, the Bible instructs us to ask God for it, and reminds us that He will answer our prayer without criticism but with abundant generosity. Hallelujah!
We need to settle it in our hearts—ahead of time—that God will supply us with wisdom in the midst of any challenging ordeal. Simply ask Him to give you the words to speak. And the wisdom that God gives to us will not be able to be opposed. (Lk 21:15) Glory to God!