“Thus says the Lord, your Redeemer, The Holy One of Israel: “I am the Lord your God, Who teaches you to profit, Who leads you by the way you should go.” (Isaiah 48:17 NKJV)
There have been times in my life when I wondered if the Lord was hearing my prayers and if He was really leading me. That's not to say that I in any way was doubting whether I was saved, but simply asking if the Lord was really leading me in the direction I needed to go. I remember being led to this passage and finally understanding that the leading of the Lord was not a feeling, but rather a daily act of personal faith on my part. Faith to trust, believe and act upon the Word of God to instruct me and direct me in the leading of the Lord.
Isaiah reminded me of six important things about the very nature and character of the God that we know and serve.
 He is the Lord, and therefore He desires to be the Lord of my life, all areas of my life.
 He is my redeemer, the one who so faithfully was willing to pay the price for my sin (all my sin) and redeem me back into the grace and forgiveness of a Holy God.
 He is the Holy One, meaning that there is no imperfection in the Father, Son and Holy Spirit. All that God does for us is within His divine and perfect will. Just as we are set apart through the work of the Cross, so the Godhead is set apart form the very sin that separated us from Him.
 He is the "I Am," what a wonderful revelation for any believer when we realize that nothing can trump the authority of God in our life. Nothing existed before Him and nothing will overshadow Him.
 He teaches us, but as Isaiah says "He teaches us to profit." I don't think that is in a materialistic way, but rather spiritually. The very nature of the word "profit" as used here means to gain. What ever I have lost in the flesh, I will gain in the Spirit.
 Lastly, and yes I think most importantly, He leads us! Not in some unorganized or random way, but according to His divine will and in agreement with His Word. God knows what He wants us to be and where He wants us to go in this life. It simply becomes a matter of obedience on our part to yield and then to follow.
"Thus says the Lord" is used some 418 times in the Old and New Testament, so obviously God has something to say to us if we will but listen and respond to His voice.