He who does justice will live in the presence of the Lord. This response to our Psalm today can also be understood to read:  He who lives in the presence of the Lord is just/does justice. I tend to think that this second rendering is easily comprehended since the first rendering might be misconstrued to mean that one has to do something to live in the presence of the Lord (of course one who is in the presence of the Lord must  present the self/act in a certain way, nonetheless, that  presence is more of a  mere being than doing). Living a just life is more of a response to God's promptings than it is a means of accessing God. It is God's graces that enables one to lead a just life, for he/she who is just lives according to the will of God. And what is the will of God?  Doing no harm to others, accepting no bribe against the innocent, not slandering with one's tongue. In other words, God's will for us is that we live justly. But we cannot say that we are living justly if we harm others, slander, or accept bribes against the innocent. We are able to live justly, not so that we live in the presence of the Lord, but rather it is our being in the presence of the Lord that enables us to lead just lives. For our lives of justice will be nothing other than our reflection of God's justice. In more human terms,  we will be doing what we see God do. As sons and daughters of God, we are already in the presence of the Lord. But staying there is our choice. We can choose to stay or move away. But if we choose to remain in God’s presence, we must act justly.