Verses with the word longsuffering in the Old Testament (4 verses):

Exodus 34:6
And the LORD passed by before him, and proclaimed, The LORD, The LORD God, merciful and gracious, longsuffering, and abundant in goodness and truth,

Numbers 14:18
The LORD is longsuffering, and of great mercy, forgiving iniquity and transgression, and by no means clearing the guilty, visiting the iniquity of the fathers upon the children unto the third and fourth generation.

Psalms 86:15
But thou, O Lord, art a God full of compassion, and gracious, longsuffering, and plenteous in mercy and truth.

Jeremiah 15:15
O LORD, thou knowest: remember me, and visit me, and revenge me of my persecutors; take me not away in thy longsuffering: know that for thy sake I have suffered rebuke.