To Be Safe-Guarded From the Devil’s Might
Jesus said to her, “Everyone who drinks of this water will be thirsty again, but whoever drinks of the water that I will give him will never be thirsty again. The water that I will give him will become in him a spring of water welling up to eternal life.”
John 4:13-14
But if we do want to boast, then let us boast that we receive from the fullness of Christ, that we are enlightened by Him, attain forgiveness of sin, and become children of God through Him. For this is the sum and substance of it all: Whoever wishes to be safe-guarded from the devil’s might and to escape sin and death must draw from this well, Christ; from Him flows all salvation and eternal bliss. This fountain is inexhaustible; it is full of grace and truth before God; it never fails no matter how much we draw from it. Even if we all dip from it without stopping, it cannot be emptied, but it remains a perennial fount of all grace and truth, an unfathomable well, an eternal fountain. The more we draw from it, the more it gives. Such water, as St. John remarks later, wells up to eternal life (John 4:14)…
This fountain constantly overflows with sheer grace. Whoever wishes to enjoy Christ’s grace—and no one is excluded—let him come and receive it from Him. You will never drain this fountain of living water; it will never run dry. You will all draw from it much more than enough, and yet it will remain a perennial well.
From Martin Luther’s Sermon on St. John – LW 22:134