God desires to produce fruit in our lives as a result of our trust in relationship with him. In order to trust in God, it involves growth in thoughts, speak, and actions. Ironically these are the same things needed to show growth in character. In order to trust God, you need to untrust yourself. When we put our trust in ourselves we cannot be trusted and makes you susceptible to failure. Putting our faith in God, (trust) we have increase. The Lord repays our trust because He is by nature trustworthy (Is. 7:9). The close similarity between vv. 7, 8 and Ps. 1:1–3 suggests that trust in the Lord entails obedience. A tree planted by water, symbolizes strength in a dry country (Is. 44:4).
The sin condemned here is trusting in man and putting that confidence in the wisdom and power, the kindness and faithfulness, of men, which should be placed in those attributes of God only. The duty required of us is to trust in the Lord and to depend upon him. When deceit, sin, threats, or the devil's little imps come knocking, we should be going to God as all-sufficient. This makes God the Lord our hope and His favor the good we hope for and His power the strength we hope in.