Our Yeast-Less Cross

Paul uses the phrase “a little leaven leavens the whole lump” in 1 Corinthians 5:6 and Galatians 5:9.  It is a familiar proverb of the day that communicates that “a small amount of leavened dough was mixed with new dough, so the yeast could spread.”  More specifically the term leaven or as the NIV puts it, yeast,  usually referred to a destructive teacher, a disparaging example or a vicious doctrine. 
What is of interest is the context that Paul uses this phrase.  He uses it in talking to the Corinthians and he also uses it when addressing the Galatians. 
In 1 Corinthians 5:1-6 we read how the Corinthian church had been tolerating sexual immorality in the congregation.  Paul accuses them of being ‘puffed up’ because they were simply allowing this sexual immorality to pass without concern.  There was no mourning over the sexual sin between a man and his step-mother.  In the words of R.C.H. Lenski there should’ve been, “grief over the devil’s success, sorrow for the congregation… mourning for the soul of the sinner who has been overwhelmed with sin and guilt.[1]”  Rather, they were arrogant and un-phased by this overt sin of this man.  The yeast had begun to leaven the whole lump.  They were being pulled away from the centrality of the yeast-less cross.
On the other side of the coin we see Paul using the same term in connection to the church of Galatia.  In Galatians 5:9 Paul applies the leaven saying to dangerous teachings.  Paul accuses the Galatia church of being bewitched.  In other words, the people of Galatia were simply swept along as if they had a spell cast over them and basically allowed the yeast to permeate without alarm.  The yeast that went unchecked in Galatia was not sexual misconduct but the advancement of a distorted gospel; more specifically a gospel that was poisoned by the yeast of man-made works righteousness.  The Galatia church received subtle injections of works-righteousness that over time permeated the whole church.  The yeast had begun to leaven the whole lump.  They were being pulled away from the centrality of the yeast-less cross.
Both of these passages speak of yeast leavening the whole lump.  Both of these passage talk about how unchecked or tolerated yeast can infect the whole church.  What was at stake in both of these churches was the Gospel, the Cross.  In laymen terms, Corinth tolerated overt sin and drifted into lawlessness, a lawlessness that undercut the Gospel.  Lawlessness essentially says, “Who needs the cross because there is no such thing as sin, I am fine!”  Galatia, on the other hand, tolerated overt works-righteousness (also sin) and drifted into legalism, a legalism that undercut the Gospel.  Legalism essentially says, “Who needs the cross because I am totally capable of fixing my own sin problem, I am fine!”  Lawlessness and legalism were the yeasts of Corinth and Galatia that were leavening or one could say destroying the whole lump, the church.
In thinking about this yeast one needs to be careful in assuming that the yeast comes solely from outside the church.  It would be convenient and na├»ve to portray the church as perfectly pure and the world as evil.  However, as we see from Mark 7:21-23 and Acts 20:29-30, the greatest threat to the church comes from within, comes from the sinful nature.  This yeast not only comes from the world but also arises within the church and when left unchecked permeates and leavens the whole lump. 
In Galatians 4:30 and 1 Corinthians 5:13 we read the words, “Purge and Cast out!”  These words are directed at the yeast!  The reason for confronting the yeast is because the beliefs of lawlessness and legalism cannot coexist with the Gospel; they spoil and undercut the Gospel.  In other words, in the expression from a phrase I once heard, “when you mix ice cream and manure, you get… manure.”  But how on earth are these doctrines continually purged.  Unfortunately at times this comes down to physical removal of a person through the last steps of church discipline, like suggested by Paul in 1 Corinthians 5.  However, in the day to day life of the body of Christ this purging happens as God’s Law Words are rightly applied and proclaimed.  When the Law of God is ministered in its second use, the theological, it acts as a mirror to expose, draw out and identify sin (Rom. 3:20).  The Holy Spirit through God’s Word of Law brings lawlessness ideology into connection with God’s perfect holiness thus exposing sin.  The Holy Spirit through God’s Word of Law also brings legalism ideology into connection with God’s perfect holiness thus exposing mankind’s depravity and inability to atone for sin.  Only then are the underlining roots of legalism and lawlessness dug up and repentance gifted to the transgressing party.  Once exposed the Holy Spirit then brings the Word of the Gospel, personally, through the means of grace so as to apply the benefits of Christ’s atoning forgiveness on the cross.   Purged and cast out!
May the yeast of legalism and lawlessness be constantly confronted by the God’s Word of Law and may we be continually granted forgiveness through God’s Gospel Words due to Christ’s Atoning Death, so that we may be continually re-centered in the centrality of the Cross.  For in the Cross, the yeast of legalism and lawlessness are continually exposed, purged and defeated.  For in the Cross we have a yeast-less place of rest, hope and security… praise be to God for His yeast-less Cross!

[1] R.C.H. Lenski, The Commentary on the New Testament: 1 & 2 Corinthians (Hendrickson, 2001), 208.