Albert Barnes Commentary Luke 2:35

"yea and a sword shall pierce through thine own soul; that thoughts out of many hearts may be revealed." — Luke 2:35 (ASV)

Yes, a sword, etc. The sufferings and death of your Son will deeply afflict your soul. And if Mary had not been forewarned in this way and sustained by strong faith, she could not have endured the trials that came upon her Son; but God prepared her for it, and the holy mother of the dying Savior was sustained.

That the thoughts, etc. This is connected with the preceding verse: He shall be a sign, a conspicuous object to be spoken against, that the thoughts of many hearts may be made manifest—that is, that they might show how much they hated holiness. Nothing so effectively brings out the feelings of sinners as telling them about Jesus Christ. Many treat Him with silent contempt; many are ready to gnash their teeth; many curse Him. All these reactions show how much the heart is by nature opposed to religion. In this way, they are really, in spite of themselves, fulfilling the Scriptures and the prophecies. So true is it that none can say that Jesus is Lord but by the Holy Ghost (1 Corinthians 12:3).