تَحْفَظُ الْأَمَانَةَ.
You safeguard the trust.
احْفَظِ الْأَمَانَةَ.
Safeguard the trust.
The first is declarative in form, while the second is a direct command. They are not interchangeable expressions of an identical speech act: one asserts a pattern of conduct, and the other requests conduct.
In some contexts a declarative form can indirectly encourage, oblige, or urge action, but that pragmatic effect requires evidence. A present-tense verb must not automatically be reclassified as an imperative merely because a directive reading would be convenient.