Telling us that the truth is in all of them
I do not believe the "truth is in all of them."
I said the truth is among the various Protestant faiths, but many are misguided or flat-out wrong.
All believers who possess Trinitarian faith in Jesus Christ as Lord and Savior are among God's elect. That faith is evidence of their salvation, not a cause of it. That's what Scripture tells us.
God's sheep are found in many disparate locations. Even among the RC church, no doubt. But I assume God will further amplify their understanding and eventually bring them into a more Scripturally-sound, Reformed Christianity.
Just so, but the sheep which are Christ's are one flock, with one Shepherd. It's one church. Not too many Christians appreciate the Shema as Jewish people do, but it is meant for all Israel.
The Whole Shema in Deut.6:4-9:
4- "Hear, O Israel: The LORD our God is one LORD;
5- and you shall love the LORD your God with all your heart, and with all your soul, and with all your might.
6- And these words which I command you this day shall be upon your heart;
7- and you shall teach them diligently to your children, and shall talk of them when you sit in your house, and when you walk by the way, and when you lie down, and when you rise.
8- And you shall bind them as a sign upon your hand, and they shall be as frontlets between your eyes.
9- And you shall write them on the doorposts of your house and on your gates.