Imagine boulders represent burdens. Sometimes we all experience the occasional heavy boulders of pain and grief: the death of a loved one; a divorce; the loss of a job. You carry your own backpack, but if a boulder rolls over onto one of your fellow hikers, you’re going to jump in and help take the load of that burden off them; you’re going to bear their burden. As you do that, you fulfill the law of Christ. The law of Christ is the law of Love. You are to love God with all your being and love your neighbor as yourself. Spiritual maturity has nothing to do with age; there are plenty of adult Christians who still cannot feed themselves.