Leviticus 2:13
And every oblation of your meat offering shall you season with salt; neither shall you suffer the salt of the covenant of your God to be lacking from your meat offering: with all your offerings you shall offer salt.
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Numbers 18:19
All the heave offerings of the holy things, which the children of Israel offer to the LORD, have I given you, and your sons and your daughters with you, by a statute for ever: it is a covenant of salt for ever before the LORD to you and to your seed with you.
Nave's Topical Index—AKJV

2 Chronicles 13:5
Ought you not to know that the LORD God of Israel gave the kingdom over Israel to David for ever, even to him and to his sons by a covenant of salt?
Nave's Topical Index—AKJV