“And in that day thou shalt say, O LORD, I will praise thee: though thou wast angry with me, thine anger is turned away, and thou comfortedst me” (Isa 12:1).
What day is that? It is the day of salvation. It’s a common expression used throughout the bible, even by Jesus Himself in John 14:20, to refer to the era after which Christ would have made provision for the salvation of mankind.
What happens “In that day?” The anger of the Lord would be turned away. The prophet also says that day will be a day of praise. We would praise God for what He has done. We would say: “Behold, God is my salvation; I will trust, and not be afraid: for the LORD JEHOVAH is my strength and my song; he also is become my salvation” (Isa 12:2).
In other words, salvation will not come by my efforts. God is my salvation. God is my song. It’s a day of praise. It’s a day of joy and singing. So he says in verse 3: “Therefore with joy shall ye draw water out of the wells of salvation.” We are to respond to, and take advantage of the salvation God has provided with thanksgiving. The fear is forever gone. He says: “I will trust, and not be afraid.” This means that my salvation will never be a matter of uncertainty. To this I respond with joy! You must do the same. Glory to God!