In "God's Word for Today" William Snider writes:

In times of difficulty, Christians have access to the grace which will enable us to stand. Remember that Peter said that our God is the God of “all grace” – all kinds and as much as we need. Are you drawing from that grace today – moment by moment? What kind of grace do you need today? Would you want to share your need with your class? We rejoice even in tribulation because “we know” that God is purposefully working in our lives to build character and confidence in Him. Consider the testimony of Job – “He knoweth the way that I take . . . I shall come forth as gold.” The rejoicing is not in the pain, but the knowing. In contrast to our one-time alienation from God, we now are enjoying His love communicated to us by the Holy Spirit.

Source: Studies in Romans: Adult Teacher's Insights, page 17.

"Though a host should encamp against me, my heart shall not fear: though war should rise against me, in this will I be confident." (Psalm 27:3)

In "Word Focus" Danny McCain writes:

The word confident in verse 3 sheds some insight into why the psalmist was not afraid. It is the word batach which “expresses that sense of well-being and security which results from having something or someone in whom to place confidence” (Theological Wordbook of the O.T.). The word does not seem to have the basic connotation of “faith” in the evangelical sense. Rather it describes a feeling of security and safety. It is used in Judges 18:7: “Then the five men departed, and came to Laish, and saw the people that were therein, how they dwelt . . . quiet and secure.”

Source: Studies in the Psalms: Adult Teacher's Insights, page 22.