The gospel is not a truth among other truths. Rather, it sets a question mark against all truths.
There will be no song on our lips if there be no anguish in our hearts.
'joy' in Phillippians is a defiant 'Nevertheless!' that Paul sets like a full stop against the Philippians' anxiety.
Grace must find expression in life, otherwise it is not grace.
He [Jesus Christ] is the Master of all as the Servant of all.
Jews have God's promise and if we Christians have it, too, then it is only as those chosen with them, as guests in their house, that we are new wood grafted onto their tree.