Humility differs from low self-esteem because the two lead us to value different, even opposite, things. 

When we suffer from low self-esteem, we start thinking that our emotions, our endeavors and even our existence have no value — such thinking is psychologically damaging and practically disempowering. For us to persevere through life’s various challenges, we need the fundamental conviction that we can make a difference. Such a conviction is not an egoistic hallucination; it is the essential human recognition that we can play some part, however small, in improving our life and possibly the lives of those around us. Gita wisdom substantiates such healthy self-esteem by declaring that we all are precious parts of the all-loving Divine, Krishna (15.07). And we all are called upon to play a part in the divine plan for the world’s welfare (11.33). 

The essence of humility is to acknowledge that we are parts and to thereafter focus on the Whole, Krishna, and on the part Krishna wants us to play. With that divine focus, we start living for a purpose bigger than ourselves. While pursuing that purpose, we will encounter obstacles and reversals or will be minimized and derided by naysayers. During such encounters, humility shields us from life’s wounds and people’s barbs. When equipped with humility, we don’t obsess over the world’s reactions to our actions; we focus on staying connected with Krishna and contributing on his behalf. Through that inner connection, we get a spiritual satisfaction that protects us from low self-esteem. Thus, we can persevere irrespective of when our outer contribution manifests as per Krishna’s inconceivable plan. 

One-sentence summary:

Low self-esteem leads us to devalue ourselves; humility leads us to value something bigger than ourselves — God and his plan for us — and empowers us to persevere in our service to him.