22. Since therefore so many indications of truth are combined, let us after the example of our fathers celebrate the festival of our general Salvation with joy and exultation, colouring our side posts, between which is the door of the word which the Apostle wishes to be opened unto him, with faith in the Lord’s Passion. Of this door David also says, _Set a watch, O Lord, before my mouth; keep the door of my lips_, that we may speak of nothing but the Blood of Christ, whereby we have conquered death, whereby we are redeemed. Let the sweet odour of Christ burn in us. To Him let us listen, on Him let us turn the eyes both of mind and body, admiring His works, proclaiming His blessings; over the threshold of our door let the confession of holy Redemption shine resplendent. Let us with fervent spirit keep the holy Feast, _in the unleavened bread of sincerity and truth_, and singing in pious ♦doctrine with one accord the Glory of the Father and of the Son and the undivided Majesty of the Holy Spirit. LETTER XXIV. A.D. 387. S. AMBROSE here reports the result of his second mission to Maximus in behalf of Justina and her son Valentinian the 2nd. He had before gone, as he mentions in this letter, immediately after the murder of Gratian, A.D. 383, and had then, at much risk to himself, done them good service, and been mainly instrumental in securing peace, and inducing Maximus to abstain from invading Italy, and to leave Valentinian in possession of a share of the Empire. Now it seemed certain that Maximus was preparing to cross the Alps and deprive Valentinian of his dominions and probably of his life, and once more Justina and her son seek the aid of the great Bishop, whom they had so cruelly persecuted during the peace he had procured for them. It is very striking to see the persecutors thus reduced to be suppliants of their victim, and the good Bishop at once rendering them the service which they sought. He writes this report while on his way back, and sends it before him, that Valentinian and his mother might learn the truth at once, and lose no time in making preparation to meet their danger. He was commissioned to induce Maximus to maintain peace, and to restore the body of Gratian for burial at Milan. S. Ambrose was less successful in this embassy than in the former one, and Justina and Valentinian had to escape to the East and put themselves under the protection of Theodosius, who took up arms in their behalf, and marched to the West, defeated and captured Maximus at Aquileia, and had him put to death, and so restored Valentinian to the Empire of all the West, A.D. 388. S. Ambrose cannot have started on his mission till after Easter, as this was the year in which he baptized S. Augustine. AMBROSE TO THE EMPEROR VALENTINIAN.