Charles H. Spurgeon on Psalms 126:5

They that sow in tears shall reap in joy. Hence, present distress must not be viewed as if it would last for ever; it is not the end, by any means, but only a means to the end. Sorrow is our sowing, rejoicing shall be our reaping. If there were no sowing in tears there would be no reaping in joy. If we were never captives we could never lead our captivity captive. Our mouth had never been filled with holy laughter if it had not been first filled with the bitterness of grief. We must sow: we may have to sow in the wet weather of sorrow; but we shall reap, and reap in the bright summer season of joy. Let us keep to the work of this present sowing time, and find strength in the promise which is here so positively given us. Here is one of the Lord's shalls and wills; it is freely given both to workers, waiters, and weepers, and they may rest assured that it will not fail: "in due season they shall reap." This sentence may well pass current in the church as an inspired proverb. It is not every sowing which is thus insured against all danger, and guaranteed a harvest; but the promise specially belongs to sowing in tears. When a man's heart is so stirred that he weeps over the sins of others, he is elect to usefulness. Winners of souls are first weepers for souls. As there is no birth without travail, so is there no spiritual harvest without painful tillage. When our own hearts are broken with grief at man's transgression we shall break other men's hearts: tears of earnestness beget tears of repentance: "deep calleth unto deep."