All must experience the bitterness of repentance, now or later.

Of course, we cannot prescribe to sinners the degree of their repentance, for an examination of the Holy Scriptures on this point will reveal that every person whose conversion is recorded there has a different degree of repentance. But every one of them must experience something of the bitterness of repentance, or he would never begin to enjoy the sweetness of the Gospel. When God leads such people to faith and salvation - without letting them experience a lot of fear and terror - He always compensates for that later. So even though God in his mercy sometimes "fast-tracks" people to faith and joy in their Savior, He sometimes by that same mercy, at a later point, drowns them in genuine sorrow over their sins, so they do not fall away from the faith.

C.F.W. Walther

Law and Gospel, CPH 2010, p. 132.