Dependence upon God to forgive and restore.
v1-3: Remembrance of past blessings; we are blessed because the Lord has blessed us; these things point us to the great blessings in Christ; favour/deliverance/forgiveness/atonement/propitiation; that is what God has done for us.
v4-9: See also Ps 77.7-9; God's work on behalf of His people; to restore, to revive, for in Him we find life itself. He gives unfailing love and salvation, and He promises peace.
There is a responsibility upon His people; we are not to return to the folly of living like unbelievers.
v10: Words fulfilled in Christ; mercy (Matt 20.30), truth (John 1.14), righteousness (1 Cor 1.30), peace (Rom 5.1); these things are perfectly balanced in Him. All these things become ours in Christ.
v11: From earth and heaven; Christ's humanity and deity combined; he is the Root and Offspring of David.
v12: The risen Christ is the first fruits (1 Cor 15.20).
v13: Perfectly righteous character; His footsteps are our pathway, not just an example to follow; but He gives strength that we might walk in obedience.