The practical use is exhorting, that we learn the doctrine of Christ with singular zeal and diligence and fortify our hearts against any corruptions thereof. As Christ is the Alpha and Omega, the beginning and the end (Rev. 1:8), so also He must be the beginning and end in our meditations and studies. Whatever you think, whatever you say, whatever you write, it has no taste unless Jesus be in it. Bernard, on Song of Songs, sermon 15, col. 532: “Every food for the soul is dry if that oil is not poured upon it. It is tasteless if it is not seasoned with this salt. If 
you write anything, it is tasteless to me unless I read Jesus there. If you argue or discuss, it has not taste for me unless Jesus sounds forth there.” On Song of Songs, sermon 34: “If you have a sense of taste, you will imitate the prudence of your bride and you will not allow this expensive packet of myrrh to be snatched from your breast even for an hour. Always remember all those bitter things that He suffered on your behalf, and consider them in your constant meditation. In this way you will be able to say, ‘That packet of myrrh so beloved to me will remain between my breasts.’ I said that it is wisdom to meditate on these things; I have established the perfection of my righteousness in these things, the fullness of wisdom in these things, the riches of salvation in these things, the abundance of merits in these things.”
Johann Gerhard, Theological Commonplaces: Exegesis IV – On Christ (5)