9 Let any man have then what he will, let him boast himself of what he will. “If I speak with the tongues of men and of Angels, but, have not charity, I have become as sounding brass, or a tinkling cymbal.” What is more sublime than the gift of various tongues? It is “brass,” it is “a tinkling cymbal,” if you take charity away. Hear other gifts; “If I should know all mysteries.” What more excellent? What more magnificent? Hear yet another; “if I should have all prophecy, and all faith, so that I could remove mountains, but have not charity, I am nothing.” He comes to still greater things, Brethren.
What else has he said? “If I should distribute all my goods to the poor.” What more perfect thing can be done? When indeed the Lord commanded the rich man this for perfection's sake, saying, “If you will be perfect, go, sell all that you have, and give to the poor.” Was he then at once perfect, because he sold all his goods and gave them to the poor? No; and therefore He added, “And come, follow Me.” “Sell all,” says He, “give to the poor, and come, follow Me.” “Why should I follow You?
Now that I have sold all, and distributed to the poor, am I not perfect? What need is there that I should follow You?” “Follow Me,” that you may learn that “I am meek and lowly in heart.” For what? Can any man sell all he has, and give to the poor, who is not yet meek, not yet lowly in heart? Assuredly he can. “For if I should distribute all my goods to the poor.” And hear still further. For some, who had left all they had and had already followed the Lord, but not yet followed Him perfectly (for to follow Him perfectly is to imitate Him), could not bear the trial of suffering.
Peter, Brethren, was already one of those who had left all and followed the Lord. For as that rich man went away in sadness, when the disciples bring troubled, asked how then any one could be perfect, and the Lord consoled them, they said to the Lord, “Behold, we have forsaken all, and followed You; what shall we have therefore?” And the Lord told them what He would give them here, what He would reserve for them hereafter. Now Peter was already of the number of those who had so done. But when it came to the crisis of suffering, at the voice of a maid-servant he denied Him thrice with whom he had promised that he was ready to die.
Source: Sermons on Selected Lessons of the New Testament (New Advent)