The good thief on the cross, a thief indeed, stole a place in heaven through the touching of a tender spot in Jesus' heart for the repentant sinner. St. Peter, prior to his commission by the Risen Jesus to feed Jesus' lambs, and prior to the Holy Spirit power he received at Pentecost, was a cowardly public denier of Jesus as the Christ. Yet, in the relentless Mercy of God, Peter became the first Pope, and a courageous martyr in imitation of his Lord and Savior.
Let's not forget Saul the bully, who became Paul the saint. And let's not overlook the countless converts to Christ, formerly avowed sinners, then repentant children of God.
Heaven isn't for the perfect.
It is for the perfected!
No one aside from the Virgin Mary dies without sin. That's why she was Assumed, for sin leads to death, and bodily corruption. Purity of heart and mind never dies. The rest of us, however, hypocrites, thieves, liars, cheats, bullies, cowards, infidels, sloths, and lukewarm disciples, need the forgiving Mercy of God to save us from death and eternal corruption.
Therefore, prayer isn't a mere good, but a necessity.
That's why sacramental confession isn't just an option, but an emergency room visit.
That's why the Eucharist isn't just an intimate option for Jesus, but what our soul should truly crave.
We all fall short of the perfection needed to enter into the pearly gates of heaven. Neither beauty, nor intelligence, nor wealth, nor power, nor strength, nor outward piety will earn us a ticket to the beatific vision.
Only faith in the Mercy of God, manifest in daily repentance, evidenced in Mercy for the poor amongst us, will suffice.
And, in the final analysis, this is all the working of God's grace.