Romans 4:21

and being absolutely certain that whatever promise He is bound by He is able also to make good.

Hebrews 11:19

For he reckoned that God is even able to raise a man up from among the dead, and, figuratively speaking, it was from among the dead that he received Isaac again.

2 Timothy 1:12

That indeed is the reason why I suffer as I do. But I am not ashamed, for I know in whom my trust reposes, and I am confident that He has it in His power to keep what I have entrusted to Him safe until that day.

Matthew 19:26

Jesus looked at them and said, "With men this is impossible, but with God everything is possible."

Luke 1:37

For no promise from God will be impossible of fulfilment."

Luke 1:45

And blessed is she who has believed, for the word spoken to her from the Lord shall be fulfilled."

Romans 8:38

For I am convinced that neither death nor life, neither the lower ranks of evil angels nor the higher, neither things present nor things future, nor the forces of nature,

Romans 14:4

Who are you that you should find fault with the servant of another? Whether he stands or falls is a matter which concerns his own master. But stand he will; for the Master can give him power to stand.

2 Corinthians 9:8

And God is able to bestow every blessing on you in abundance, so that richly enjoying all sufficiency at all times, you may have ample means for all good works.

Hebrews 11:13

All these died in the possession of faith. They had not received the promised blessings, but had seen them from a distance and had greeted them, and had acknowledged themselves to be foreigners and strangers here on earth;

Treasury of Scripture Knowledge

Summary

And being fully persuaded that, what he had promised, he was able also to perform.

Bible References

Fully

Romans 8:38
For I am convinced that neither death nor life, neither the lower ranks of evil angels nor the higher, neither things present nor things future, nor the forces of nature,
2 Timothy 1:12
That indeed is the reason why I suffer as I do. But I am not ashamed, for I know in whom my trust reposes, and I am confident that He has it in His power to keep what I have entrusted to Him safe until that day.
Hebrews 11:13
All these died in the possession of faith. They had not received the promised blessings, but had seen them from a distance and had greeted them, and had acknowledged themselves to be foreigners and strangers here on earth;

He was able

Romans 14:4
Who are you that you should find fault with the servant of another? Whether he stands or falls is a matter which concerns his own master. But stand he will; for the Master can give him power to stand.
Matthew 19:26
Jesus looked at them and said, "With men this is impossible, but with God everything is possible."
Luke 1:37
For no promise from God will be impossible of fulfilment."
2 Corinthians 9:8
And God is able to bestow every blessing on you in abundance, so that richly enjoying all sufficiency at all times, you may have ample means for all good works.
Hebrews 11:19
For he reckoned that God is even able to raise a man up from among the dead, and, figuratively speaking, it was from among the dead that he received Isaac again.