וְהֶאֱמִן בַּֽיהוָה וַיַּחְשְׁבֶהָ לּוֹ צְדָקָֽה׃
And he was believing in the Lord, and he counted it to him as righteousness. (Genesis 15:6)
In this Hebrew verse, the first word וְהֶאֱמִן starts with a וְ (waw conjunction) meaning “and.” The rest of the word הֶאֱמִן is a hiphil perfect verb from the basic root אמן meaning “firmness” or “certainty.” In the hiphil stem it means “stand firm,” “trust” or “believe.” Typically, the hiphil stem describes causative action or the causing of an event by an agent. The hiphil stem is in the active voice, and the key words “caused” or “made” are often inserted. For example, “they caused to kill” or “they made someone king.” However, the hiphil stem may also express a simple action which would preserve the qal stem meaning and negate the causative meaning mentioned above. This is most likely the case with הֶאֱמִן in this sentence, but verbal aspect must also be considered to understand the reason for the hiphil stem and to determine the meaning of הֶאֱמִן.
For this discussion, it is important to focus on two forms of verbal aspect in Biblical Hebrew: qatal and wayyiqtol. The qatal aspect is associated with the perfect designation to express a state or a condition that requires duration or repetiton or to view a situation or action as a complete whole that is temporally undefined. The wayyiqtol aspect involves an imperfect verb plus waw consecutive. In general, an imperfect verb denotes an incomplete action or describes an event without the end in view, but when an imperfect verb is prefixed with waw consecutive, it will be translated with a similar aspect as a perfect verb.
Next, it is important to point out that these two forms are often together in narrative. According to H.H. Hardy,
wayyiqtol verbs depict the mainline events of a narrative. The story is moved along from one event to another using successive wayyiqtol verbs. When additional setting material, contrasting statements, summaries, epexegetical remarks, background information, or any out-of-sequence occurrence is provided, the sequence is interrupted by a switch in verbal form. If this information is also perfective, then the verbal form is qatal.
This is the sequence of the general context leading up to הֶאֱמִן in Genesis 15:6. In the first few sentences of the narrative of Chapter 15, Abram and God are having conversation
(v.2) Abram said (wayyiqtol verb)
(v.3) Abram said (wayyiqtol verb)
(v.4) God took Abraham outside and said (wayyiqtol verbs)
(v.5) God said (wayyiqtol verb)
(v.6) (Abram) he was believing הֶאֱמִן (qatal verb)
This shows the verbal form switch of Genesis 15:6, but this switch goes undetected in most english versions of the Bible that translate הֶאֱמִן in 15:6 as “he believed.” This is certainly within the translation possibilities of the hiphil perfect (qatal) form. As mentioned above, the hiphil stem can express a simple action like the qal stem, but the interruption of verbal sequencing points to the writer trying to emphasize something in the narrative. The writer switches to the qatal aspect to emphasize Abram’s belief in the Lord as a complete whole that is temporally undefined. Abram did not start to believe in the Lord at this point in the narrative, rather Abram started believing in the Lord in Genesis 12. For Abram, believing in the Lord was not a one time thing in 15:6, nor was it finalized at this point, but it was a repetitious process of believing. Thus, an appropriate translation of הֶאֱמִן is “he was believing.” The writer uses וְהֶאֱמִן “and he was believing” to emphasize that Abram’s faith was a journey. His journey of faith wasn’t perfect, but Abram was believing in the Lord, and it was because of this believing that the Lord “counted it to him as righteousness.”
Just like Abram’s faith, the Christian faith is not a one time thing, but a journey of believing. It is a life of trusting in the promises of God. We are living and growing in belief, and we are called friends of God.
 R. L. Harris, Jr. Gleason L. Archer, and Bruce K. Waltke, אָמַן in Theological Wordbook of the Old Testament (Chicago: Moody Pub, 2003), 51. Francis Brown, S. R. Driver, Charles A. Briggs, אָמַן in The Brown-Driver-Briggs Hebrew and English lexicon (Peabody: Hendrickson Publishers, 2001), 52. Bill T. Arnold and John H. Choi, A Guide to Biblical Hebrew Syntax (Cambridge: Cambridge University Press, 2018), 49. Gary D. Pratico and Miles V. Pelt, Basics of Biblical Hebrew Grammar (Grand Rapids: Zondervan, 2009), 345. Pratico and Pelt, BBH, 346. Victor P. Hamilton, The Book of Genesis, Chapters 1-17, NICOT Series (Grand Rapids: Wm. B. Eerdmans Publishing, 1990), 424. Arnold and Choi, Guide to Biblical, 54-55. Ronald J. Williams and John C. Beckman, Williams’ Hebrew Syntax (Toronto: University of Toronto Press, 2007), 69. Arnold and Choi, Guide to Biblical, 84. H. H. Hardy, Exegetical Gems from Biblical Hebrew: A Refreshing Guide to Grammar and Interpretation (Grand Rapids: Baker Academic, 2019), EPUB edition, ch. 9, “Overview of Perfect Verbs.”