God is merciful, all the time.
Sacred Scripture, and the Sacrament of Reconciliation (confession) attest to this.
The Prodigal Father always longs for us to return to Him, and constantly graces us with the necessary internal impetus for us to see the poverty of life without Him. His Love is free, His Mercy abundant, and His memory of our transgressions nonexistent.
Yet, like in the parable, we have elder brothers and sisters too.
Unlike God, they don't always long for us to return, and, quite often, they send us unnecessary external impetus for us to stay away. Since they have the same sinful impulses as us, the Prodigal son (or daughter), they struggle to offer unconditional Love; rather, it is conditioned, as is their mercy, by many subtle, and not so subtle, human factors.
And their memory, well, let's just say, it is healthy.
The goal for us then, a good Lenten goal, is to try and remember that God and our elder brother, or sister, are two differing realities (though they don't have to be--and, when hearts are open to the Holy Spirit, they are almost indiscernible). God invites us, prodigals and elders, into His Merciful Life through the Eucharistic Life of the Church. This is where we become less of a judge, and more like the Savior. Yet, and this is true of everyone--prodigals and elders--our transformation in the Perfection of Jesus' Sacrificial Love is an ongoing, lifelong struggle.
In the meantime, we must juggle two realities: we must have a paradoxical compassion on our (justifiably) judgmental elders while we differentiate God's Mercy and their ecclesial (Church) presence.