Wrath is God’s holy response to sin: His personal, active antagonism to sin that derives from His settled opposition to every evil thing. It is therefore right - and even necessary - for God to hate sin, to oppose all wickedness, and to judge all who practice it.
Some think that the idea of wrath is unjust or unbecoming to a God of love. This is largely because we underestimate both the extent and the seriousness of sin and the holiness of God. Not only is God perfectly justified in His wrath, but without it, His very character would be compromised. It would contradict His nature to not punish sin. If God failed to punish sin, He would cease to be just. If He ceased to be just, He would cease to be a loving God.