My oldest son is getting pimples, and calls me dad now instead of daddy. My daughter is becoming a beautiful young lady, and my youngest while still in diapers is using engaging in regular conversation and no longer in baby mode. Meanwhile I think the 1990's were still just a decade ago, while my body has aches when I wake up in the morning to remind me I'm not in my twenties anymore. While my wife and I hope to stay young forever by continuing to just keep having children, biology has it's own race against time and so we realize these stages the kids are moving through may be the last time we see it.
It serves as a good reminder not to take things for granted. But it's easy said than done. We DO take things for granted--our time, health, and our family. We don't say I love you enough, and we kick the can down the road to make resolve on amending our lives. We leave the house in the morning and then someone doesn't come back in the evening as the result of an accident or tragedy. Our resolve to say the things we always wanted, give the biggest hug we've ever given, gets truncated while our regret at not doing so fans out on the waters of memory in perpetua.
I think this is why our Lord makes a point to bring children to his lap and hold them up as models of the Kingdom servants. The Israelites and the prophets would leave memorial altars (Joshua 4:1-11; 1 Kings 18: 30-31) to constantly leave evidence of God's salvific work in their history. If we are made to be like children in order to enter the Kingdom (Mt 18:3), we must remember what it was like to wear diapers and nurse.
The Japanese harbinger of Zen Buddhism to West, D.T. Suzuki, referred to this practice of essential recollection as "Beginner's Mind." The process of awaking, of "seeing things as they are" is the ultimate aim of Zen. In this school of Buddhism, enlightenment happens in a flash of insight (aided by daily meditation and the working of koans, or Zen riddles), and the tablecloth is whipped off in an instant leaving the china in tact on top.
For the Christian, our "beginner's mind" is the recollection of our saving by grace. This occurs in baptism (as infants or adults), but eventually the fog rolls back in and our intellects are clouded by personal sin. We have moments of repentance--mini baptisms--when we are wiped clean of those stains and have the opportunity to begin anew and never look back to the trough from which we were gorging. Sin is essentially forgetting--offenses against God whom we forget is the reason for our being. We forget what make us truly happy and settle for counterfeits. We forget what we have been saved from.
There is no greater joy for me, or remembrance of my own ransoming from death, then to witness a new convert coming into the Faith. Yes, there is joy in the ceremonial rite at the Easter Vigil. But even more so, there is the observance of a changed heart of stone that has experienced a fissure. It could be a tragedy, a loss of control in a particular circumstance, or simply a recognition of our dependence on grace that makes someone question the road they are currently traveling on. When they wake up to grace and experience true metanoia in a lonely hotel room or on the floor of a drug den or suburban kitchen, it is really a birthing floor. The gestation may take months or years, but when one is truly "born again," their beginner's heart has been forged, as the Lord says, "I will give you a new heart, and put a new spirit within you" (Ez 36:26).
The excitement of a pure-hearted convert is contagious. "Did you know that the rosary is really a meditation on Scripture? Did you know that baptism washes away Original Sin? Wow!" Yes, we know. We know intellectually, and we know from reading the Catechism. We may have known for years, or even all our life. But we know it on a surface level, because we have forgotten the basics.
That is why to attain a beginner's heart, we cannot forget. When our prayer becomes rote and our spirit tired, the "diaper days" of a baby Christian can be our memorial altars where we observe that God is still working in His people to bring about salvation for all mankind. We can share in their fundamental joy and wonder by stripping off our airs and simply sitting at the feet of Christ in prayer and adoration, as a child sits at her's mother's feet listening to her read.
We can drink for the first time again, hear for the first time again we may have heard thousands of time before. Because the scriptures as living Word, and the Eucharist as the Living Bread, does not grow stale or mold but has the power to renew even the most accustomed spirit, we can become babes again, be born again, over and over. It is not our bodies that reincarnate in future lives, but our heart and spirit that regenerate in this life to prepare us for our Judgement when we will no longer see through a glass darkly, but will know even we are known (1 Cor 13:12), and sit before the Judge stripped naked as the day we were born.
