In the Scriptures
Betach (בֶּטַח) and Bittachon (בִּטָּחוֹן) express a sense of well-being and security that results from placing confident expectation in God. The ancient Greek translation of the Torah (i.e., the Septuagint) never translates words deriving from this root in terms of merely "believing in God" (i.e., intellectual assent), but in terms of hoping or relying upon God's emunah (faithfulness) as the only true Source of hope. As the Psalms repeatedly state, the confidence that comes from relying upon God is valid only because of God's chesed (his loyalty or covenantal faithfulness).
Some of the Jewish sages have said that bittachon can be of two forms: "active" bittachon and "passive" bittachon. Active bitachon is self-confidence to carry out actions and goals we set for ourselves. However, it is by God's grace that we are enabled to do anything at all, and this recognition leads to passive bitachon, namely, the confidence that God will work all things together for good to those who are trusting in Him (Rom. 8:28).