Acts 23:10-11 (KJV)
10 And when there arose a great dissension, the chief captain, fearing lest Paul should have been pulled in pieces of them, commanded the soldiers to go down, and to take him by force from among them, and to bring him into the castle.
11 And the night following the Lord stood by him, and said, Be of good cheer, Paul: for as thou hast testified of me in Jerusalem, so must thou bear witness also at Rome.

This happened when and after Paul was before the council. For more background have a read of Acts 22:30, 23:1-22. Paul was in great danger and there was not much hope in him going to Rome as the LORD put this desire in is heart.
“Acts 19:21 (KJV) After these things were ended, Paul purposed in the spirit, when he had passed through Macedonia and Achaia, to go to Jerusalem, saying, After I have been there, I must also see Rome.”

Many times in scripture we see GOD confirming and affirming His promises of what He will do despite of what we see and our circumstances are. We also can expect GOD to show up and affirm His promise and give us a word to help us through the hard times so we do not loose fight of the goal He has given us. He imparts to us a gift of faith so that we know with 100% certainty that what GOD has promised He will do. In Hebrews 11 we can see a whole summary of this. “Hebrews 11:11 (KJV) Through faith also Sara herself received strength to conceive seed, and was delivered of a child when she was past age, because she judged him faithful who had promised.”

Therefore let us be encouraged and know that GOD who promises is faithful and He will give us the faith and strength to see through whatever we are going through. Let us look beyond our circumstances to the LORD Jesus Christ and His promises.
“2 Corinthians 1:20-22 (KJV) For all the promises of God in him are yea, and in him Amen, unto the glory of God by us. [21] Now he which stablisheth us with you in Christ, and hath anointed us, is God; [22] Who hath also sealed us, and given the earnest of the Spirit in our hearts.”