Without question salvation is of the Lord [YHWH] (Jonah 2:9; Ex. 14:13; 2 Chron. 20:17; Lam. 3:26; etc.). While that is indisputable, it is terrible how that basic truth has been twisted to support Calvinism, a theology which hangs or falls with all five points being interrelated!
Because Calvinists believe God elects those to be saved and those to be lost (double predestination), to them the Biblical phrase salvation is of the Lord is most supportive. 
That has also led to their error that man has no free will in his own personal salvation — a distortion and misrepresentation of grace, salvation, etc. Salvation comes from the Lord, but many Scriptures show man has freewill and choice in salvation. For example, in Mark 10:21,22 the rich, young ruler was called by the Lord himself to follow Jesus, yet of his own free will he turned and walked away from Jesus without eternal life! Jesus wanted him saved, called him to follow, but he chose of his own free will to reject. He wasn’t willing to pay the price to have the hidden treasure in the field – salvation. The truth is man having free will doesn’t affect God’s sovereignty for he has always allowed man to wisely choose or foolishly reject the salvation from the Lord.
Remember folks, even the devil quotes Scripture sometimes! A Scripture must be considered in context and in harmony with all other verses on the same subject to assure truth. That being said, Calvinism distorts various Scriptures, including the ones which say salvation is of the Lord, but there is more.
Salvation is of the Lord is For The Righteous Only
The salvation of the righteous comes from the LORD; he is their stronghold in time of trouble. (Psa 37:39)
Salvation is far from the wicked, for they do not seek out your decrees. (Psa 119:155)
Salvation Is Of The Lord For The RIGHTEOUS
Salvation is of the LORD is for the righteous only, not the wicked (or unrighteous) too! Please check the list of unrighteous people in 1 Cor. 6:9,10. (IF you are listed there repent immediately.) An additional characteristic of the wicked, based on Psa. 119:155, is they do not seek out God’s decrees. There is no salvation of the Lord for them!
