Albert Schweitzer said this quote

I look back upon my youth and realize how so many people gave me help, understanding, courage – very important things to me – and they never knew it. They entered into my life and became powers within me. All of us live spiritually by what others have given us, often unwittingly, in the significant hours of our life. At the time these significant hours may not even be perceived. We may not recognize them until years later when we look back, as one remembers some long-ago music or a boyhood landscape. We all owe to others much of the gentleness and wisdom that we have made our own; and we may well ask ourselves what will others owe to us.