John Calvin Commentary Psalms 118:13

"Thou didst thrust sore at me that I might fall; But Jehovah helped me." — Psalms 118:13 (ASV)

You have sorely thrust at me. He either now changes the person addressed, or directs his discourse to Saul, his principal enemy. In the person of one, he defies all his enemies together. In saying that he had been thrust at, he admits that he did not withstand the attack by his own bravery. Those who are powerful enough to encounter opposition sustain the assaults of their enemies without flinching. The power of God is more gloriously displayed in raising him up even from ruin itself.

In the following verse, he draws the conclusion that God is his strength and song. By the first of these terms, he candidly acknowledges his weakness and ascribes his safety exclusively to God. And having admitted that his strength was in God alone (because he was sustained by God's power), he immediately adds that God is his praise or his song. This latter phrase must be understood in a passive sense. “In myself there was no ground for boasting; to God belongs entirely all the praise of my safety.” The last clause of the verse, where he says that God was his salvation, refers to the same subject.