3. What the effect of them will be: I will pour upon them the Spirit of grace. One would think that it should follow, "And they shall look on him whom they have believed, and shall rejoice" (and it is true that that is one of the fruits of the pouring out of the Spirit, whence we read of the joy of the Holy ghost), but it follows, They shall mourn; for there is a holy mourning, that is the effect of the pouring out of the Spirit, a mourning for sin, which is of use to quicken faith in Christ and qualify for joy in God. It is here made the matter of a promise that they shall mourn, for there is a mourning that will end in rejoicing and has a blessing entailed upon it. This mourning is a fruit of the Spirit of grace, an evidence of a work of grace in the soul, and a companion of the Spirit of supplication, as it expresses lively affections working in prayer; hence prayers and tears are often put together, 2 Kings xx. 5. Jacob, that wrestler with God, wept and made supplication. But here it is a mourning for sin that is the effect of the pouring out of the Spirit.