08812 Infinitive
There are two forms of the infinitive:
1a1) as subject to keep the judgments to seek thy heart
1a2) as object in his "writing" he spoke, "saying"
1b1) Used with a verb to emphasize the verbal idea. This is often rendered by an English adverb, such as, "surely", "utterly".
he will surely visit you he utterly destroyed the people
1b2) It may be used by itself with the value of a finite form of the verb, especially an imperative.
remember the sabbath day