Lord Allah will say: "This is the Day on which the truthful will be benefited their Truth, for them have Paradise beneath which rivers are flowing, they will live in it forever, Allah has pleased with them and they have pleased with Him, that is a great triumph".
Those who testified the Truth Adhikr after receiving It, are the heedful as told in verse 39: 33. While those who reject Adhikr after receiving It, are the wrongdoers and disbelievers whose destiny is Hell as told in verse 39: 32. I.e. Truth means Adhikr. The heedful and truthful are those who are following and testifying Adhikr as explained in verse 2: 180. It is told in verses 9: 100: 58: 22, and 98: 8 that the Lord has pleased with the believers and they also pleased with Him. It is told in verses 89: 27-30 that the Lord will tell the believer at the time of his death: "Oh the tranquil soul, return to your Lord by pleasing Him and pleased by Him. So you enter in My service, and you enter in My Paradise".
See explanation 2: 25; 3: 95, 136, and 4: 87.