The pictures from Sunday Morning Preview are needed to understand this sermon (click here to listen). It would also be good to read the scriptures -- Genesis 17:1-7,15-17, Psalm 22:23-32, Romans 4:13-25 and Mark 8:31-38.
Even when we are weak in faith, even when we waver as Abraham did -- contrary to the common translation of Romans 4:20* -- in his feelings (see Gen 17:17), we can trust our Lord to love and rescue us.
That's the amazing good news of God.
*Note on Romans 4:20. In Greek (εἰς δὲ τὴν ἐπαγγελῒαν τοῦ θεοῦ οὐ διεκρίθη τῇ ἀπιστίᾳ ἀλλʼ ἐνεδυναμώθη τῇ πίστει, δοὺς δόξαν τῷ θεῷ) this verse includes the words οὐ διεκρίθη which are often translated "not waver" or "not doubt." "διεκρίθη," however, is better connected with the idea of "playing the judge." In the case of Romans 4:20, then, it would mean that Abraham didn't "judge" for himself that God couldn't keep his promises. Abraham, and every person of faith, does have feelings that waver, doubt and even despair from time to time. But faith says "even though I doubt you, God, even though all my feelings say I'm lost, your Word tells me that you can rescue and carry me anyway, so I wait for your promise to come true."