Whether you are picking beans or preaching sermons, you will always have a mingling of critics and supporters offering their two cents about your methods.  In either case, you can get distracted from the work you are doing by pausing for too long to listen to either opinion.  To remain focused on the task before you, it's best to turn a blind eye and a deaf ear to the competing voices whenever possible, and to reflect instead on the Lord's voice as spoken though the Gospel. 

Resources:

"The Blind Eye and the Deaf Ear" in "Lectures to My Students" by Charles Spurgeon http://www.thekinnardhomestead.com/the-blind-eye-and-the-deaf-ear-charles-spurgeon

 "The Cross and Criticism" by Alfred J. Poirier http://www.thekinnardhomestead.com/the-cross-and-criticism-alfred-j-poirier