Contradiction with Matthew 9:37
John 4:35 speaks of the fields being ready for harvest now, whereas Matthew 9:37 talks about laborers being few, suggesting that the readiness for harvest is not as widespread or certain.
Matthew 9:37: Then saith he unto his disciples, The harvest truly [is] plenteous, but the labourers [are] few;
Contradiction with Mark 4:29
John 4:35 mentions that the fields are already ready for harvest, while Mark 4:29 indicates a process where the crop must first mature before the immediate harvest.
Mark 4:29: But when the fruit is brought forth, immediately he putteth in the sickle, because the harvest is come. [brought...: or, ripe]
Contradiction with Ecclesiastes 3:2
John 4:35 stresses immediate harvesting, but Ecclesiastes 3:2 discusses a set time for every activity, including harvesting, suggesting a natural order rather than urgency.
Ecclesiastes 3:2: A time to be born, and a time to die; a time to plant, and a time to pluck up [that which is] planted; [to be...: Heb. to bear]