Our Gemara on Amud Aleph notes that the Hebrew form of Yeshalem (“He shall pay”) connotes being involuntarily forced to pay, as opposed to the passive tense, Yushlam (“Payment shall occur” or “It shall be paid”).

The Sefer Daf al Daf quotes a question from the Parashas Derachim (Derush 26). Rus Rabbah (5:4) records a seemingly superfluous comment on the following verse (Rus 2:12):

יְשַׁלֵּ֥ם ה׳ יְשַׁלֵּ֥ם יְהֹוָ֖ה פׇּעֳלֵ֑ךְ וּתְהִ֨י מַשְׂכֻּרְתֵּ֜ךְ שְׁלֵמָ֗ה מעם ה׳ אלקי יִשְׂרָאֵ֔ל אֲשֶׁר־בָּ֖את לַחֲס֥וֹת תַּֽחַת־כְּנָפָֽיו

May the LORD reward your deeds. May you have a full recompense from the LORD, the God of Israel, under whose wings you have sought refuge.

Says Rav Chassah: “In that you sought to shelter under His wings.” 

What is Rav Chassah adding that the verse doesn’t already state?

An additional question regarding Boaz’s assertion that God will reward. Since Boaz used the directive tense “Yeshalem”, it is as if he is ordering God to make payment. What moral basis makes Boaz so sure that God owes Rus anything? Vayikra Rabbah (27:2) quotes a verse in Iyov (41:3):

מִ֣י הִ֭קְדִּימַנִי וַאֲשַׁלֵּ֑ם תַּ֖חַת כׇּל־הַשָּׁמַ֣יִם לִי־הֽוּא׃

Who has a claim on me from before, that I should repay him? whatever is under the whole heaven is mine.

The Midrash elaborates on this idea that God owes us nothing, by speaking for God: “Who puts on a mezuzah without first having a home? Who fulfills the mitzvah of placing a guard rail on their roof without first having a roof over their heads?” Meaning, God gives you all the benefits of living, and thus the mitzvos are US paying HIM back for what He has already done for us. So God does not owe us any reward. Yet, the Midrash (Bamidbar Rabbah, Naso 14) indicates an instance where God behaves as if He is obligated to pay: “One who has inadequate funds yet still gives charity, and one who does not have children yet still supports the local cheder.” In that case, God obligates Himself to grant such a person wealth or children in response to their selfless leap of faith.

Parashas Derachim says that Rus’ choice to convert was completely voluntary. True, God gave her the gift of life, but as she was not yet part of the Jewish covenant, she was only obligated in the Seven Noahide laws. Her choice to take on all the mitzvos was an example of the kind of leap of faith that God obligates Himself to reward. This is why Boaz could speak with such surety.

On a practical level, we cannot be as sure as Boaz, and should never assume that God owes us anything. Our observance and faith might not be pure enough to merit such miraculous affirmation (see Kiddushin 39b). It is notable that the Midrash believes one who makes the commitment to support a mitzvah even before God provides the means to act on it is a great merit toward being granted miraculous reward. This explains the theological value in committing to action that supports the desired goal for others, even when that same goal is personally being held back. For example, assisting others who suffer from a particular life circumstance or illness that is similar to the one you experience can create this merit, such as people who are childless donating to orphanages or someone with a terminal illness supporting cancer victims. We cannot demand from God in an absolute sense, but it does seem like we can be persuasive.