Since you know the will of God,
act according to it and you will be blessed.
. . .
It is not a part of the Psalm, I admit, but an antiphon. Still, it struck me deeply, as I have just come from teaching on the sacraments. Maybe at first blush it seems unrelated, but I teach in an ecumenical setting. Occasionally I have to answer for the Roman Catholic view of the Eucharist, not so much the doctrine but the exclusiveness of the table. Transubstantiation bothers people less than the idea that some might be excluded from the Lord's table.
Sometimes it's difficult.
At the end of the day, though, what we have to answer for is our own practice. Knowing the theology, knowing the doctrine, places a particular responsibility on me as a teacher and as a Christian. I know why I receive communion in my parish and other Catholic churches, and why I refrain in other settings. I can explain it, though not always to everyone's satisfaction.
Sometimes it's difficult, but the antiphon reminded me why listening to my conscience is important. If only I content myself with what, to the best of my knowledge, is the will of God, and act accordingly, I have done what I can. I may be corrected, I may see things differently tomorrow, but today I have to listen to his voice.
Let it be done to me according to His will.