The heart is deceitful above all things,
and desperately sick;
who can understand it?
- Jeremiah 17:9 (ESV)
As I was reading Spurgeon's Cheque Book of Faith this morning, the Scripture "promise" that was listed was Matthew 26:33 - 'Peter answered and said unto him, Though all men shall be offended because of thee, yet will I never be offended.'
Spurgeon already anticipated my complaint: "What kind of a promise is that?", and proceeded to remind me that the promises of men are not to be trusted, lending even more weight to the promises of God. He ends the day's meditation with these words:
Trust not thyself nor any born of woman, beyond due bounds; but trust thou only and wholly in the Lord.
My promises may fail, due to the deceitful nature of my heart, but the promises of God never fail.