“My flesh and my heart may fail, but God is the strength of my heart and my portion forever” (Psalm 73:26, ESV). In Psalm 73, the eternal hope of the righteous is contrasted with the temporal prosperity of the wicked. The psalmist reflects at length on how evil men seem to get away with their wrongdoing, and prosper in this life (vv.4-12). But his thoughts changed when he “discerned their end” (v.17), that God brings them to destruction (vv.18-20). So the psalmist turns to reflection on fellowship with God and eternal hope in Him (vv.23-25), leading to these words of confidence.
God is the unfailing Redeemer of those who trust in Him. In ourselves we are weak, but in Him we can be strong to stand firm amidst the trials and temptations of this life. Trust in the Lord, and be of good hope; make Him your deepest desire, and take refuge in His Almighty strength.