C. F. W. Walther was the first President of the Lutheran Church--Missouri Synod and its most influential theologian. He wrote these paragraphs to encourage Christians who think little of the promises God made them in Baptism.
Oh, that every one of us would... let himself be brought to faith in the promises once given him in his Baptism!
Baptism's unrealized treasure
You who do not believe though you have been baptized, what riches of grace and salvation God has given you already. Yet you do not consider or desire them! You belong in God’s kingdom Yet you willfully want to remain in the kingdom of darkness! The dove of the Holy Spirit has brought you, like an olive branch of peace, into the ark of the Christian Church. Yet you would rather wither and fade.
Oh, open your eyes and return to your Baptism!
Then God will be your God and Father again. Your sins will be drowned in the sea of grace. And your Baptism will be the door to heaven.
Baptism's unrealized strength
But you who indeed believe, though you believe in weakness, know this: you have in your Baptism a glorious means of strengthening. Consider this: even if everything becomes doubtful and uncertain, your Baptism stands fast. It happened once, and God does not go back on his Word. There God has, so to speak, made himself your captive.
Only do not let him go; do not let your hand of faith let go of his covenant of grace. He cannot leave you.
What he has so dearly spoken
Never shall by him be broken;
Firmly stands his covenant.
So let not your faith be stifled
Or by flesh and Satan rifled;
God’s hand holds you confident.