Bernard lived most of his life in the twelfth century. Because it is easy in the internet age to find biographical information on St. Bernard, I will just note that what Martin Luther admired about him was his non-scholastic theology, which was rooted in biblical exposition. Most of all Luther admired Bernard unabashed preaching that salvation comes by grace through faith in Jesus Christ. Almost four hundred years before Luther's heyday, the so-called Mellifluous (i.e., "Honey-tongued) Doctor was preaching and teaching a form of sola gratia/sola fidei.
The question arises that if we are saved by grace alone through faith alone and if faith, along with hope and love, being a theological virtue, is a free gift that God bestows on whomever He chooses, then what part, if any, do we play? The first thing to note about this, which distinguished Catholics and probably most Lutherans from Calvinists, is that God does not force His grace on anyone. While it is important not to reduce faith to mere belief, the free decision to believe, to initially respond to God's grace is certainly the beginning of faith. St. Paul's conversion, as recorded in Acts 9, gives us good insight into how faith is a response to God's initiative, which we call grace.
After seeing the flash of a bright light, which caused him to fall on the ground, and hearing the voice of Jesus asking Saul why he was persecuting Him by persecuting His Body, the Church, the Risen Lord immediately tells Saul, "Now get up and go into the city and you will be told what you must do" (Acts 9:6). As Saul and those who accompanied him understood it, "the city" is Damascus, where he was headed to continue his zealous persecution of Jewish Christians. We learn that those who were traveling with Saul heard the voice, but did not see anyone. Heeding the voice, they took Saul "by the hand" and "brought him to Damascus" (Acts 9:7-8). What we take away from this is that Saul, as well as those with him, heard the voice of the Lord and obeyed. Were they not all, including Saul, free to return to Jerusalem? I think this is a great beginning to understanding faith as our response to God's initiative towards us, even though we are forced to acknowledge that God, in His wisdom, most often uses subtler means.
What is saved, according to St. Bernard, is free choice: "Take away free choice and there is nothing to be saved. Take away grace and there is no means of saving.... God is the author of salvation, the free choice is merely capable of receiving it: None but God can give it, nothing but free choice receive it" (Liber de gratia et libero arbitrio "Book of grace and free will"). St. Bernard continued, "For to consent is to be saved. Where you have consent, there also is the will. But where the will is, there is freedom. And this is what I understand by the term 'free choice.'"
While there is certainly more to unpack here, especially within the context of Bernard's own theology, I find this convergence promising, a fertile field for the cultivation of Christian unity.