In Psalm 23:4, David wrote, 'Yea, though I walk through the valley of the shadow of death, I will fear no evil; For You are with me; Your rod and Your staff, they comfort me'. The expression 'the valley of the shadow of death' here speaks of 'the darkness (or challenges) one walks through in life at times', and the word 'evil' here is 'rah' in Hebrew, literally meaning 'adversity, trouble'.
People of God, if you are faced with any 'adversity' or 'trouble' in the world right now, fear not, because the Lord your God is with you; and His rod and His staff, they comfort you. He uses His rod to chase away your 'predators', and His staff to lead (and guide) you to the right direction. Like sheep to the shepherd, keep looking to Him and trusting in Him, your Good Shepherd (Psalm 23:1-3), no matter what happens around you. He has been there for you, and He will still be with you! Be rest assured. David knew this very well, and no wonder he wrote at the beginning of this psalm, 'The Lord is my shepherd; I shall not be in want' (Psalm 23:1).
By the time David wrote Psalm 23, he must have already seen much in life. He was no more a youngster. How do I know? In Psalm 23:5, he wrote, 'You prepare a table before me in the presence of my enemies...' This means he's old enough to have enemies. I mean, real enemies in this world! In the same verse, he also wrote, 'You anoint my head with oil; My cup runs over'. This means he's old enough to have experienced abundance in providence. In Psalm 23:6, he wrote, 'Surely goodness and mercy shall follow me all the days of my life; And I will dwell in the house of the Lord forever'. This means he's old enough to have tasted much of the Lord's goodness and mercy for him to write this way!
He must have also reminisced how the Lord had been there for him in his earlier days, even as far back as the time when he faced Goliath! He was still in his youth when Goliath came out from the camp of the Philistines and challenged Israel to choose a man to fight him (1 Samuel 17:8). However, all the men of Israel fled from him (Goliath) and were dreadfully afraid (1 Samuel 17:24), for he was a giant, and his height was 'six cubits and a span', equivalent to 'nine feet and six inches' in modern-day measurement!
But David 'stepped up to the plate', even though Goliath was about twice his size, and as 'intimidating' as can be! David knew the battle wasn't his, but the Lord's (1 Samuel 17:47), and he prevailed (1 Samuel 17:50-51). When king Saul heard about it, he sent Abner, the commander of the army of Israel, to inquire about him (1 Samuel 17:56-58).
You see, what the enemy meant as an 'opposition' against Israel, the Lord turned it around as a 'promotion' time for His beloved, David!
The name 'Goliath' comes from the Hebrew word 'galah', meaning 'to shame, to strip (in a disgraceful sense), to remove'. So, if your 'Goliath' comes against you in order to shame you, strip you (in a disgraceful sense), and remove you (from God's plan and purposes in your life), fear not, because just as He was with David those days, the Lord is now here with you, fighting the battles for you. In fact, the Lord has a good news for you: "Your 'promotion' time is coming!"
