Necessary. This word is in the emphatic position in the Greek.
Beforehand. In this verse Paul stresses the importance of completing the collection prior to his arrival. Evidently he feared there might be some procrastination in completing the job. With this verse he brings his tactful, wise, and firm pressure to a climax. It is not simply money that is at stake, or the needs of the poor. It is the spirit and character of the Corinthians, their Christian maturity. True giving is an act of the soul. It awakens the higher manhood within one. It tends to crucify the flesh and the lust of selfishness. It cleanses and purifies the giver from base motives. It is one of the principal avenues to happiness and mental health. Every true gift given with an eye to God’s glory and to the happiness of others will result in blessings to the giver.
Covetousness. That is, a greedy desire to have more. Paul warns the Corinthians against giving grudgingly some small amount, merely to make an impression and gain an advantage. See on Luke 12:15.