I'm sorry for your loss, orThis came from most everyone, but more from Israelis and the religious.
I'm sorry to hear about your father
The next most popular condolences were the traditional Jewish ones:
May God comfort you (among the mourners of Jerusalem and Zion) / may you be comforted,One non-Jewish friend offered the first one of these to me.
May his memory be a blessing, or
Blessed be the true judge
In third place was the phrase:
Please accept my condolences / sympathies / commiserationsStrangely, only Jews offered this version. The last one was offered by one weird friend.
The least popular was:
My thoughts / prayers are with youI thought this was going to be in second place, but I was wrong. This phrase was offered only by Americans: non-religious Jews or other friends (the "prayers" variant by religious Christians).
Oddly, no one offered this (apparently deprecated) form of condolence:
Our hearts go out to you during your time of sorrowNor any other form of heart, e.g. "you are in our hearts". Hearts appear to be passe.