Acts 2:26

Again, David expressly (or rather the Lord in the person of the saint, and the same from the foundation of the world is each one who at different periods is saved, and shall be saved by faith) says, "My heart was glad, and my tongue rejoiced, and my flesh shall still rest in hope. For Thou shalt not leave my soul in hell, nor wilt Thou give Thine holy one to see corruption. Thou hast made known to me the paths of life, Thou wilt make me full of joy in Thy presence." As, then, the people was precious to the Lord, so also is the entire holy people; he also who is converted from the Gentiles, who was prophesied under the name of proselyte, along with the Jew.

For the assertion, "Seeing that it was not possible that He should be holden of it," means this, that His rising was not common to the rest. Then, however, before their thoughts can enter at all into his meaning, he brings David upon them, an authority which sets aside all human reasoning. "For David saith (with reference) to Him." And observe how, once more, the testimony is lowly. For therefore he begins the citation further up, with the matters of lowlier import therefore was death not in the number of grievous things [because], says he, "I foresaw the Lord always before my face, that He is on my right hand that I should not be moved:" and, "that Thou wilt not leave my soul in hell."

Because implies that the Lord stood at his right hand, and He testifies that delight has arisen in His thoughts and joy on His tongue. Perfect joy is that which is both conceived in a joyful heart and brought forth in eager speech. Just as He used the word moreover of His evils, so he repeated the word of His blessings, so that humanity might be thought to have received heavenly joys according to the measure of His human troubles. For He says that His joy has welled over His gladness because the suffering flesh which He took up for the salvation of all of us has corruption.

Moreover, my flesh will not fail in destruction, but will sleep in the hope of resurrection. For You will not leave my soul to be possessed by Hell, nor will You allow Your Holy One's body, through which others too are sanctified, to see corruption.

For this reason my heart was delighted, and my tongue exulted. For this reason, because He, indeed, stood at the right hand, and He attests that in His thoughts, joy and exultation arose in His tongue. And indeed, as the passion was threatening, He said: "My soul is sorrowful unto death," and He began to fear and be weary (Mark 14). But He was sorrowful to show that He was truly man in soul and body, and truly passible; but His soul and tongue exulted because He knew that by His passion the human race was to be saved.

Moreover, even my flesh will rest in hope. Indeed, He was rejoicing that He could not be moved or overcome by enemies; but beyond this joy, He declares that His joy increased even more in that He was to provide an example of resurrection in His flesh, by which He saved us through His death.

"Even my flesh shall rest in hope."
Since Jesus, having accepted death, put off that flesh which He had assumed according to the plan of the economy, in order to raise it again from death, it is fitting that His flesh nourished itself with hope in expectation of the resurrection.