I'm just a laywoman, but I don't recall being taught that sacramental grace is something that should make our communities look outwardly nicer, or have better works, which is what you seem to think should be the corollary to such a belief.
Regardless of doctrine, every community struggles with sin. I haven't found a single Christian denomination where members don't struggle with some sin or other. It's why so many unbelievers don't hold to the faith in any shape or form -- they always say, I see people just as nice and moral without Christianity as those who claim to be of the faith!
Right, the declared righteousness of God--our justification before God--is about our forgiveness. Not about our works. Good works ought to proceeds from faith, and indeed it's a serious problem if they don't; but our status and position in Christ comes entirely by way of Christ's finished work and His righteousness which is ours as pure grace. So that the grace of God in Word and Sacrament are about God declaring us righteous for Christ's sake. God is shouting from all four corners of the Church, "I forgive you!"
When we step outside and into the world, as parents, children, friends, neighbors, doctors, lawyers, or retail store workers (or anything) we now are invited to live out what we have received for our neighbor. To take up our cross and follow Christ.
When we fall short, when we fail (and we do, of course we do) we are confronted by the brutal truth of the Law that we are sinners in need of God's mercy, and so we confess and repent, seeking our only salvation in Jesus daily. Because of His faithfulness to us. Which is why, again, we hear the word, we receive the Supper, we remember our baptism, etc. Because, as already said, God is here declaring us forgiven for Christ's sake, there is grace here because Christ suffered and died for us, and God loves us and keeps us in faith, in Christ, by the power and work of the Holy Spirit.
So daily we cling to Christ, for in Him alone is hope and salvation and forgiveness and justification before God.
Even when we fail, God's faithfulness does not falter.
Some wrongly think that this means we are therefore free to live sinful and lawless lives; but it's just the opposite. Paul reminds us in Romans 6 that in light of God's grace in our baptism we are to reckon ourselves dead to sin and alive to God; no longer slaves to sin, but slaves of righteousness. "Shall we go on sinning that sin may abound? Heaven forbid!" is what he says.
It's that when we sin, we don't have to be defeated and destroyed and have our guilty conscience lead us to despair and away from faith and hope in Jesus; it's that when we sin we can come boldly before the Throne of Grace in repentance, and the word of God comes to us: "Your sins are forgiven".
The role of good works, then, factor not into who we are before God in Christ; but rather who we are before our neighbor in love--as disciples of Christ, servants and subjects of our Lord.
I need Jesus every hour of every day. Just like that hymn says, "Jesus I need Thee, every hour I need Thee". That's the grace of God in Word and Sacrament.
And in that word I can trust that, even though it is not always obvious to me, God is working His good work in me. Without that faith, without that grace, without the Holy Spirit I would not even want to love God and love my neighbor. Without that I would not even confess I am a sinner. So no matter how wretched I might behold myself in the mirror of the Law, I can be comforted by God's grace and love for me in Christ, which He declares to me all day long in Word and Sacrament. And I can put one step forward, without being broken and dying on the side of the road, because Jesus carries and holds me. But it is from Him that my heart is being cleansed and changed, that my mind is being renewed. And while I may not perceive that I am a "good person" as though I were without fault or struggle or temptation or failure, I can trust that He is faithful, He is working, He is keeping me, and calling me, and inviting me day by day to follow Him. And He is my Help, my Physician, and my Refuge.
That my flesh is daily scourged and mortified in repentance. And my heart and mind are daily renewed by grace that I might behold His grace which is forever set before me in the plain and simple gifts of God: Word and Sacrament.
"
For Thou art with me, Thy rod and Thy staff they comfort me."
-CryptoLutheran