Baptism and Grace

Karl Barth quoting Martin Luther:

'Your baptism is nothing less than grace clutching you by the throat: a grace-full throttling, by which your sin is submerged in order that ye may remain under grace. Come thus to thy baptism. Give thyself up to be drowned in baptism and killed by the mercy of thy dear God, saying "Drown me and throttle me, dear Lord, for henceforth I will gladly die to sin with Thy Son"' (Luther). This death [in Rom 6:3-4] is grace. - Karl Barth, The Epistle to the Romans(Oxford: 1968), 194.