Veteran disciples experience the same dynamic; they get stronger the longer they walk in God’s ways. They develop spiritual muscle allowing them to more easily deal with tests, temptations, and difficulties that would have been harder to conquer earlier in their walk. As their trust in God grows, they are able to weather longer periods of adversity; they grow in spiritual stamina.
That pattern is reflected in scripture. Moses started out hesitant in Exodus chapters 3 and 4, but grew increasingly strong as he followed the course God laid out for him. Jesus repeatedly, and in different contexts, taught that “[a]ny one who has will be given more [.]” Matthew 13:12 (New Jerusalem Bible). See also Matthew 25:29; Mark 4:25; Luke 8:18 and 19:26. Peter went from denying Jesus on Good Friday to boldly proclaiming Him in very threatening circumstances. See Acts 4:1-22; 5:29-33,40-42.
Just as there’s no denying that “[i]n this world you will have hardship,” John 16:33 (New Jerusalem Bible), there’s also no doubt that God increasingly strengthens those who diligently follow Him.