“The Lord and His prophets and apostles lived in a culture that often used salt to ratify everyday agreements. Salt symbolizes fidelity and constancy. When the Lord Jesus announces that “every sacrifice will be seasoned with salt,” He tells us that genuine trials cannot be successfully met without fidelity and constancy. The way to be ready for fire is to train ourselves in the practice of stability. The Holy Spirit offers this gift to the earnest, struggling Christian. Our Lord identifies the salt of faithfulness as a means to “peace with one another.” (Dynamis 1/20/2014)
“By calling his disciples salt, Jesus is telling them that they are a valuable and necessary part of God’s plan. He is calling on them to add fullness and flavor to Christian life, to preserve the faith they have received and pass it on to others. The disciples are called to be living proof of God's love on earth. This means they are as basic to God’s word as salt is to human life, and if the disciples can’t be salt, then they will not be true disciples living as God desires them.” (Pam Lobely)
“Our spirit should be quick to reach out toward God, not only when it is engaged in meditation; at other times, also, when carrying out its duties, caring for the needy, performing works of charity, giving generously in service of others, our spirit should long for God and call Him to mind, so that these works may be seasoned with the salt of God’s love, and so make a palatable offering to the God of the universe. Throughout the whole of our lives, we may enjoy the benefit that comes from prayer if we devote a great deal of time to it.” (St. John Chrysostom)
“We should make a difference in the “flavor” of the world we live in, just as salt changes meat’s flavor...We should counteract the moral decay in society, just as salt preserves food from decay. When we lose this desire to “salt” the earth with the love and message of God, we become useless to Him." (Life Application Study Bible, Mark 9:50)
“Salt and light illustrate the role of disciples in society. Because of its preservative powers, its necessity for life, and its ability to give flavor, salt had religious and sacrificial significance (Lv 2:13; see also Nm 18:19; 2Ch 13:5). To eat salt with someone meant to be bound together in loyalty. As the salt of the earth, Christians are preservers of God's covenant and give true flavor to the world.” (Orthodox Study Bible, Matthew 5:13-16)