Charles H. Spurgeon on Psalms 49:5

Wherefore should I fear in the days of evil, when the iniquity of my heels shall compass me about? The man of God looks calmly forward to dark times when those evils which have dogged his heels shall gain a temporary advantage over him. Iniquitous men, here called in the abstract iniquity, lie in wait for the righteous, as serpents that aim at the heels of travellers: the iniquity of our heels is that evil which aims to trip us up or impede us. It was an old prophecy that the serpent should wound the heel of the woman's seed, and the enemy of our souls is diligent to fulfil that premonition. In some dreary part of our road it may be that evil will wax stronger and bolder, and gaining upon us will openly assail us; those who followed at our heels like a pack of wolves, may perhaps overtake us, and compass us about. What then? Shall we yield to cowardice? Shall we be a prey to their teeth? God forbid. Nay, we will not even fear, for what are these foes? What indeed, but mortal men who shall perish and pass away? There can be no real ground of alarm to the faithful. Their enemies are too insignificant to be worthy of one thrill of fear. Doth not the Lord say to us, "I, even I, am he that comforteth thee; who art thou, that thou shouldest be afraid of a man that shall die, and of the son of man which shall be made as grass?" Scholars have given other renderings of this verse, but we prefer to keep to the authorised version when we can, and in this case we find in it precisely the same meaning which those would give to it who translate my heels, by the words "my supplanters."